Publications by Dimitra Rigopoulou


A multi-wavelength view of the star formation activity at z ∼ 3

Astrophysical Journal 714 (2010) 1740-1745

GE Magdis, D Elbaz, E Daddi, GE Morrison, M Dickinson, D Rigopoulou, R Gobat, HS Hwang

We present a multi-wavelength, UV-to-radio analysis for a sample of massive (M * ∼ 1010 M ⊙) IRAC- and MIPS 24 μm detected Lyman break galaxies (LBGs) with spectroscopic redshifts z 3 in the GOODS-North field. For LBGs without individual 24 μm detections, we employ stacking techniques at 24 μm, 1.1mm, and 1.4GHz to construct the average UV-to-radio spectral energy distribution and find it to be consistent with that of a luminous infrared galaxy with L IR = 4.5 +1.1-2.3 × 1011 L ⊙ and a specific star formation rate of 4.3 Gyr-1 that corresponds to a mass doubling time 230 Myr. On the other hand, when considering the 24 μm detected LBGs we find among them galaxies with L IR>10 12 L ⊙, indicating that the space density of z 3 UV-selected ultra-luminous infrared galaxies (ULIRGs) is (1.5 0.5) × 10-5 Mpc-3. We compare measurements of star formation rates from data at different wavelengths and find that there is tight correlation (Kendall's τ>99.7%) and excellent agreement between the values derived from dust-corrected UV, mid-IR, millimeter, and radio data for the whole range of L IR up to L IR 1013 L ⊙. This range is greater than that for which the correlation is known to hold at z ∼ 2, possibly due to the lack of significant contribution from polycyclic aromatic hydrocarbons to the 24 μm flux at z ∼ 3. The fact that this agreement is observed for galaxies with L IR> 1012 L ⊙ suggests that star formation in UV-selected ULIRGs, as well as the bulk of star formation activity at this redshift, is not embedded in optically thick regions as seen in local ULIRGs and submillimeter-selected galaxies at z = 2. © 2010 The American Astronomical Society. All rights reserved.


In-flight calibration of the Herschel-SPIRE instrument

Astronomy and Astrophysics 518 (2010)

BM Swinyard, A Dowell, M Ferlet, D Griffin, S Guest, K King, S Leeks, TL Lim, C Pearson, E Polehampton, D Rigopoulou, S Ronayette, S Sidher, P Ade, M Griffin, K Isaak, A Papageorgiou, M Pohlen, A Rykala, L Spencer, J-P Baluteau, D Benielli, D Pouliquen, MJ Barlow, G Savini, R Wesson, GJ Bendo, M Trichas, J Bock, D Dowell, H Nguyen, D Brisbin, A Conley, L Conversi, I Valtchanov, T Fulton, P Imhof, J Glenn, M Zemcov, L Levenson, N Lu, B Schulz, A Schwartz, D Shupe, CK Xu, L Zhang, S Jones, G Makiwa, D Naylor, S Oliver, AJ Smith, H Aussel, P Panuzzo, H Triou, H Roussel, A Woodcraft, A Glauser, B Sibthorpe

SPIRE, the Spectral and Photometric Imaging REceiver, is the Herschel Space Observatory's submillimetre camera and spectrometer. It contains a three-band imaging photometer operating at 250, 350 and 500 μm, and an imaging Fourier-transform spectrometer (FTS) covering 194-671 μm (447-1550 GHz). In this paper we describe the initial approach taken to the absolute calibration of the SPIRE instrument using a combination of the emission from the Herschel telescope itself and the modelled continuum emission from solar system objects and other astronomical targets. We present the photometric, spectroscopic and spatial accuracy that is obtainable in data processed through the "standard" pipelines. The overall photometric accuracy at this stage of the mission is estimated as 15% for the photometer and between 15 and 50% for the spectrometer. However, there remain issues with the photometric accuracy of the spectra of low flux sources in the longest wavelength part of the SPIRE spectrometer band. The spectrometer wavelength accuracy is determined to be better than 1/10th of the line FWHM. The astrometric accuracy in SPIRE maps is found to be 2 arcsec when the latest calibration data are used. The photometric calibration of the SPIRE instrument is currently determined by a combination of uncertainties in the model spectra of the astronomical standards and the data processing methods employed for map and spectrum calibration. Improvements in processing techniques and a better understanding of the instrument performance will lead to the final calibration accuracy of SPIRE being determined only by uncertainties in the models of astronomical standards. © 2010 ESO.


Herschel-ATLAS: Evolution of the 250 mu m luminosity function out to z = 0.5

ASTRONOMY & ASTROPHYSICS 518 (2010) ARTN L10

S Dye, L Dunne, S Eales, DJB Smith, A Amblard, R Auld, M Baes, IK Baldry, S Bamford, AW Blain, DG Bonfield, M Bremer, D Burgarella, S Buttiglione, E Cameron, A Cava, DL Clements, A Cooray, S Croom, A Dariush, G de Zotti, S Driver, JS Dunlop, D Frayer, J Fritz, JP Gardner, HL Gomez, J Gonzalez-Nuevo, D Herranz, D Hill, A Hopkins, E Ibar, RJ Ivison, MJ Jarvis, DH Jones, L Kelvin, G Lagache, L Leeuw, J Liske, M Lopez-Caniego, J Loveday, S Maddox, MJ Michalowski, M Negrello, P Norberg, MJ Page, H Parkinson, E Pascale, JA Peacock, M Pohlen, C Popescu, M Prescott, D Rigopoulou, A Robotham, E Rigby, G Rodighiero, S Samui, D Scott, S Serjeant, R Sharp, B Sibthorpe, P Temi, MA Thompson, R Tuffs, I Valtchanov, PP van der Werf, E van Kampen, A Verma


Herschel unveils a puzzling uniformity of distant dusty galaxies

Astronomy and Astrophysics 518 (2010)

D Elbaz, HS Hwang, B Magnelli, E Daddi, H Aussel, B Altieri, A Amblard, P Andreani, V Arumugam, R Auld, T Babbedge, S Berta, A Blain, J Bock, A Bongiovanni, A Boselli, V Buat, D Burgarella, N Castro-Rodriguez, A Cava, J Cepa, P Chanial, RR Chary, A Cimatti, DL Clements, A Conley, L Conversi, A Cooray, M Dickinson, H Dominguez, CD Dowell, JS Dunlop, E Dwek, S Eales, D Farrah, N Förster Schreiber, M Fox, A Franceschini, W Gear, R Genzel, J Glenn, M Griffin, C Gruppioni, M Halpern, E Hatziminaoglou, E Ibar, K Isaak, RJ Ivison, G Lagache, D Le Borgne, E Le Floc'H, L Levenson, N Lu, D Lutz, S Madden, B Maffei, G Magdis, G Mainetti, R Maiolino, L Marchetti, AMJ Mortier, HT Nguyen, R Nordon, B O'Halloran, K Okumura, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Perez Fournon, AM Pérez García, A Poglitsch, M Pohlen, P Popesso, F Pozzi, JI Rawlings, D Rigopoulou, L Riguccini, D Rizzo, G Rodighiero, IG Roseboom, M Rowan-Robinson, A Saintonge, M Sanchez Portal, P Santini, M Sauvage, B Schulz

The Herschel Space Observatory enables us to accurately measure the bolometric output of starburst galaxies and active galactic nuclei (AGN) by directly sampling the peak of their far-infrared (IR) emission. Here we examine whether the spectral energy distribution (SED) and dust temperature of galaxies have strongly evolved over the last 80% of the age of the Universe. We discuss possible consequences for the determination of starformation rates (SFR) and any evidence for a major change in their star-formation properties. We use Herschel deep extragalactic surveys from 100 to 500 μm to compute total IR luminosities in galaxies down to the faintest levels, using PACS and SPIRE in the GOODS-North field (PEP and HerMES key programs). An extension to fainter luminosities is done by stacking images on 24 μm prior positions. We show that measurements in the SPIRE bands can be used below the statistical confusion limit if information at higher spatial resolution is used, e.g. at 24 μm, to identify isolated ± galaxies whose flux is not boosted by bright neighbors. Below ∼1.5, mid-IR extrapolations are correct for star-forming galaxies with a dispersion of only 40% (0.15 dex), therefore similar to ∼0 galaxies, over three decades in luminosity below the regime of ultra-luminous IR galaxies (ULIRGs, LIR ¡Ý 1012 L). This narrow distribution is puzzling when considering the range of physical processes that could have affected the SED of these galaxies. Extrapolations from only one of the 160 μm, 250 μm or 350 μm bands alone tend to overestimate the total IR luminosity. This may be explained by the lack of far-IR constraints around and above ∼150 μm (rest-frame) before Herschel on those templates. We also note that the dust temperature of luminous IR galaxies (LIRGs, LIR 10 11 L) around ∼1 is mildly colder by 10̈C15% than their local analogs and up to 20% for ULIRGs at ∼1.6 (using a single modified blackbody-fit to the peak far-IR emission with an emissivity index of ≥ = 1.5). Above z = 1.5, distant galaxies are found to exhibit a substantially larger mid-over far-IR ratio, which could either result from stronger broad emission lines or warm dust continuum heated by a hidden AGN. Two thirds of the AGNs identified in the field with a measured redshift exhibit the same behavior as purely star-forming galaxies. Hence a large fraction of AGNs harbor coeval star formation at very high SFR and in conditions similar to purely star-forming galaxies. © 2010 ESO.


HerMES: Halo occupation number and bias properties of dusty galaxies from angular clustering measurements

Astronomy and Astrophysics 518 (2010)

A Cooray, A Amblard, L Wang, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, V Buat, D Burgarella, N Castro-Rodriguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, CD Dowell, E Dwek, S Eales, D Elbaz, D Farrah, M Fox, A Franceschini, W Gear, J Glenn, M Griffin, M Halpern, E Hatziminaoglou, E Ibar, K Isaak, RJ Ivison, AA Khostovan, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, G Marsden, K Mitchell-Wynne, AMJ Mortier, HT Nguyen, B O'Halloran, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Perez Fournon, M Pohlen, JI Rawlings, G Raymond, D Rigopoulou, D Rizzo, IG Roseboom, M Rowan-Robinson, B Schulz, D Scott, P Serra, N Seymour, DL Shupe, AJ Smith, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, M Vaccari, I Valtchanov, JD Vieira, L Vigroux, R Ward, G Wright, CK Xu, M Zemcov

We measure the angular correlation function, w(θ), from 0.5 to 30 arcmin of detected sources in two wide fields of the Herschel Multi-tiered Extragalactic Survey (HerMES). Our measurements are consistent with the expected clustering shape from a population of sources that trace the dark matter density field, including non-linear clustering at arcminute angular scales arising from multiple sources that occupy the same dark matter halos. By making use of the halo model to connect the spatial clustering of sources to the dark matter halo distribution, we estimate source bias and halo occupation number for dusty sub-mm galaxies at z ∼ 2. We find that sub-mm galaxies with 250 μm flux densities above 30 mJy reside in dark matter halos with mass above (5±4)×10 12 M ⊙ , while (14±8)% of such sources appear as satellites in more massive halos. © ESO 2010.


HerMES: Far infrared properties of known AGN in the HerMES fields

Astronomy and Astrophysics 518 (2010)

E Hatziminaoglou, A Omont, JA Stevens, A Amblard, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, V Buat, D Burgarella, N Castro-Rodríguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Dye, S Eales, D Elbaz, D Farrah, M Fox, A Franceschini, W Gear, J Glenn, EA González Solares, M Griffin, M Halpern, E Ibar, K Isaak, RJ Ivison, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, AMJ Mortier, HT Nguyen, B O'Halloran, SJ Oliver, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Pérez-Fournon, M Pohlen, JI Rawlings, D Rigopoulou, D Rizzo, IG Roseboom, M Rowan-Robinson, M Sanchez Portal, B Schulz, D Scott, N Seymour, DL Shupe, AJ Smith, M Symeonidis, M Trichas, KE Tugwell, M Vaccari, I Valtchanov, L Vigroux, L Wang, R Ward, G Wright, CK Xu, M Zemcov

Nuclear and starburst activity are known to often occur concomitantly. Herschel-SPIRE provides sampling of the far-infrared (FIR) spectral energy distributions (SEDs) of type 1 and type 2 AGN, allowing for the separation between the hot dust (torus) and cold dust (starburst) emission. We study large samples of spectroscopically confirmed type 1 and type 2 AGN lying within the Herschel Multi-tiered Extragalactic Survey (HerMES) fields observed during the science demonstration phase, aiming to understand their FIR colour distributions and constrain their starburst contributions. We find that one third of the spectroscopically confirmed AGN in the HerMES fields have 5σ detections at 250 μm, in agreement with previous (sub)mm AGN studies. Their combined Spitzer-MIPS and Herschel-SPIRE colours (specifically S 250 /S 70 vs S 70 /S 24 ) quite clearly separate them from the non-AGN, star forming galaxy population, as their 24 μm flux is dominated by the hot torus emission. However, their SPIRE colours alone do not differ from those of non-AGN galaxies. SED fitting shows that all those AGN need a starburst component to fully account for their FIR emission. For objects at z > 2 we find a correlation between the infrared luminosity attributed to the starburst component, L SB , and the AGN accretion luminosity, L acc , with L SB proptoL acc0.35 . Type 2 AGN detected at 250 μm show on average higher L SB than type 1 objects but their number is still too low to establish whether this trend indicates stronger star formation activity. © 2010 ESO.


The HerMES SPIRE submillimeter local luminosity function

Astronomy and Astrophysics 518 (2010)

M Vaccari, L Marchetti, A Franceschini, B Altieri, A Amblard, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, V Buat, D Burgarella, N Castro-Rodríguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Dye, S Eales, D Elbaz, D Farrah, M Fox, W Gear, J Glenn, EA González Solares, M Griffin, M Halpern, E Hatziminaoglou, J Huang, E Ibar, K Isaak, RJ Ivison, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, AMJ Mortier, HT Nguyen, B O'Halloran, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Pérez-Fournon, M Pohlen, JI Rawlings, G Raymond, D Rigopoulou, D Rizzo, G Rodighiero, IG Roseboom, M Rowan-Robinson, M Sánchez Portal, B Schulz, D Scott, N Seymour, DL Shupe, AJ Smith, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, E Valiante, I Valtchanov, L Vigroux, L Wang, R Ward, G Wright, CK Xu, M Zemcov

Local luminosity functions are fundamental benchmarks for high-redshift galaxy formation and evolution studies as well as for models describing these processes. Determining the local luminosity function in the submillimeter range can help to better constrain in particular the bolometric luminosity density in the local Universe, and Herschel offers the first opportunity to do so in an unbiased way by imaging large sky areas at several submillimeter wavelengths. We present the first Herschel measurement of the submillimeter 0 < z < 0.2 local luminosity function and infrared bolometric (8-1000 μm) local luminosity density based on SPIRE data from the HerMES Herschel key program over 14.7 deg 2 . Flux measurements in the three SPIRE channels at 250, 350 and 500 μm are combined with Spitzer photometry and archival data. We fit the observed optical-to-submillimeter spectral energy distribution of SPIRE sources and use the 1/V max estimator to provide the first constraints on the monochromatic 250, 350 and 500 μm as well as on the infrared bolometric (8-1000 μm) local luminosity function based on Herschel data. We compare our results with modeling predictions and find a slightly more abundant local submillimeter population than predicted by a number of models. Our measurement of the infrared bolometric (8-1000 μm) local luminosity function suggests a flat slope at low luminosity, and the inferred local luminosity density, 1.31 -0.21+0.24 × 10 8 L ⊙ Mpc -3 , is consistent with the range of values reported in recent literature. © 2010 ESO.


The HerMES SPIRE submillimeter local luminosity function

Astronomy and Astrophysics 518 (2010)

M Vaccari, L Marchetti, A Franceschini, B Altieri, A Amblard, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, V Buat, D Burgarella, N Castro-Rodríguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Dye, S Eales, D Elbaz, D Farrah, M Fox, W Gear, J Glenn, EA González Solares, M Griffin, M Halpern, E Hatziminaoglou, J Huang, E Ibar, K Isaak, RJ Ivison, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, AMJ Mortier, HT Nguyen, B O'Halloran, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Pérez-Fournon, M Pohlen, JI Rawlings, G Raymond, D Rigopoulou, D Rizzo, G Rodighiero, IG Roseboom, M Rowan-Robinson, M Sánchez Portal, B Schulz, D Scott, N Seymour, DL Shupe, AJ Smith, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, E Valiante, I Valtchanov, L Vigroux, L Wang, R Ward, G Wright, CK Xu, M Zemcov

Local luminosity functions are fundamental benchmarks for high-redshift galaxy formation and evolution studies as well as for models describing these processes. Determining the local luminosity function in the submillimeter range can help to better constrain in particular the bolometric luminosity density in the local Universe, and Herschel offers the first opportunity to do so in an unbiased way by imaging large sky areas at several submillimeter wavelengths. We present the first Herschel measurement of the submillimeter 0 < z < 0.2 local luminosity function and infrared bolometric (8-1000 μm) local luminosity density based on SPIRE data from the HerMES Herschel key program over 14.7 deg2. Flux measurements in the three SPIRE channels at 250, 350 and 500?m are combined with Spitzer photometry and archival data. We fit the observed optical-to-submillimeter spectral energy distribution of SPIRE sources and use the 1/Vmax estimator to provide the first constraints on the monochromatic 250, 350 and 500?m as well as on the infrared bolometric (81000 μm) local luminosity function based on Herschel data. We compare our results with modeling predictions and find a slightly more abundant local submillimeter population than predicted by a number of models. Our measurement of the infrared bolometric (8-1000 7mu;m) local luminosity function suggests a flat slope at low luminosity, and the inferred local luminosity density, 1.31+0.24-0.21× 108 L-Mpc-3, is consistent with the range of values reported in recent literature. © 2010 ESO.


HerMES: The SPIRE confusion limit

Astronomy and Astrophysics 518 (2010)

HT Nguyen, B Schulz, L Levenson, A Amblard, V Arumugam, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, V Buat, N Castro-Rodriguez, A Cava, P Chanial, E Chapin, DL Clements, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Eales, D Elbaz, M Fox, A Franceschini, W Gear, J Glenn, M Griffin, M Halpern, E Hatziminaoglou, E Ibar, K Isaak, RJ Ivison, G Lagache, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, G Marsden, J Marshall, B O'Halloran, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Perez Fournon, M Pohlen, N Rangwala, D Rigopoulou, D Rizzo, IG Roseboom, M Rowan-Robinson, D Scott, N Seymour, DL Shupe, AJ Smith, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, M Vaccari, I Valtchanov, L Vigroux, L Wang, R Ward, D Wiebe, G Wright, CK Xu, M Zemcov

We report on the sensitivity of SPIRE photometers on the Herschel Space Observatory. Specifically, we measure the confusion noise from observations taken during the science demonstration phase of the Herschel Multi-tiered Extragalactic Survey. Confusion noise is defined to be the spatial variation of the sky intensity in the limit of infinite integration time, and is found to be consistent among the different fields in our survey at the level of 5.8, 6.3 and 6.8 mJy/beam at 250, 350 and 500 μm, respectively. These results, together with the measured instrument noise, may be used to estimate the integration time required for confusion limited maps, and provide a noise estimate for maps obtained by SPIRE. © 2010 ESO.


HerMES: SPIRE galaxy number counts at 250, 350, and 500 μ m

Astronomy and Astrophysics 518 (2010)

SJ Oliver, L Wang, AJ Smith, B Altieri, A Amblard, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, V Buat, D Burgarella, N Castro-Rodríguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Eales, D Elbaz, M Fox, A Franceschini, W Gear, J Glenn, M Griffin, M Halpern, E Hatziminaoglou, E Ibar, K Isaak, RJ Ivison, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, K Mitchell-Wynne, AMJ Mortier, HT Nguyen, B O'Halloran, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Pérez-Fournon, M Pohlen, JI Rawlings, G Raymond, D Rigopoulou, D Rizzo, IG Roseboom, M Rowan-Robinson, M Sánchez Portal, R Savage, B Schulz, D Scott, N Seymour, DL Shupe, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, M Vaccari, E Valiante, I Valtchanov, JD Vieira, L Vigroux, R Ward, G Wright, CK Xu, M Zemcov

Emission at far-infrared wavelengths makes up a significant fraction of the total light detected from galaxies over the age of Universe. Herschel provides an opportunity for studying galaxies at the peak wavelength of their emission. Our aim is to provide a benchmark for models of galaxy population evolution and to test pre-existing models of galaxies. With the Herschel Multi-tiered Extra-galactic survey, HerMES, we have observed a number of fields of different areas and sensitivity using the SPIRE instrument on Herschel. We have determined the number counts of galaxies down to ~20 mJy. Our constraints from directly counting galaxies are consistent with, though more precise than, estimates from the BLAST fluctuation analysis. We have found a steep rise in the Euclidean normalised counts <100 mJy. We have directly resolved ~15% of the infrared extra-galactic background at the wavelength near where it peaks. © 2010 ESO.


HerMES: Halo occupation number and bias properties of dusty galaxies from angular clustering measurements

Astronomy and Astrophysics 518 (2010)

A Cooray, A Amblard, L Wang, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, V Buat, D Burgarella, N Castro-Rodriguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, CD Dowell, E Dwek, S Eales, D Elbaz, D Farrah, M Fox, A Franceschini, W Gear, J Glenn, M Griffin, M Halpern, E Hatziminaoglou, E Ibar, K Isaak, RJ Ivison, AA Khostovan, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, G Marsden, K Mitchell-Wynne, AMJ Mortier, HT Nguyen, B O'Halloran, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Perez Fournon, M Pohlen, JI Rawlings, G Raymond, D Rigopoulou, D Rizzo, IG Roseboom, M Rowan-Robinson, B Schulz, D Scott, P Serra, N Seymour, DL Shupe, AJ Smith, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, M Vaccari, I Valtchanov, JD Vieira, L Vigroux, R Ward, G Wright, CK Xu, M Zemcov

We measure the angular correlation function, w(θ), from 0.5 to 30 arcmin of detected sources in two wide fields of the Herschel Multi-tiered Extragalactic Survey (HerMES). Our measurements are consistent with the expected clustering shape from a population of sources that trace the dark matter density field, including non-linear clustering at arcminute angular scales arising from multiple sources that occupy the same dark matter halos. By making use of the halo model to connect the spatial clustering of sources to the dark matter halo distribution, we estimate source bias and halo occupation number for dusty sub-mm galaxies at z ∼ 2. We find that sub-mm galaxies with 250 μm flux densities above 30 mJy reside in dark matter halos with mass above (5±4)×1012 M⊙, while (14±8)% of such sources appear as satellites in more massive halos. © 2010 ESO.


HerMES: The submillimeter spectral energy distributions of Herschel/SPIRE-detected galaxies

Astronomy and Astrophysics 518 (2010)

B Schulz, CP Pearson, DL Clements, B Altieri, A Amblard, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, V Buat, D Burgarella, N Castro-Rodríguez, A Cava, P Chanial, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Eales, D Elbaz, M Fox, A Franceschini, W Gear, E Giovannoli, J Glenn, M Griffin, M Halpern, E Hatziminaoglou, E Ibar, K Isaak, RJ Ivison, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, G Marsden, AMJ Mortier, HT Nguyen, B O'Halloran, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, I Pérez-Fournon, M Pohlen, N Rangwala, JI Rawlings, G Raymond, D Rigopoulou, D Rizzo, IG Roseboom, M Rowan-Robinson, M Sánchez Portal, D Scott, N Seymour, DL Shupe, AJ Smith, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, M Vaccari, E Valiante, I Valtchanov, L Vigroux, L Wang, R Ward, G Wright, CK Xu, M Zemcov

We present colours of sources detected with the Herschel/SPIRE instrument in deep extragalactic surveys of the Lockman Hole, Spitzer-FLS, and GOODS-N fields in three photometric bands at 250, 350 and 500 μm. We compare these with expectations from the literature and discuss associated uncertainties and biases in the SPIRE data. We identify a 500 μm flux limited selection of sources from the HerMES point source catalogue that appears free from neighbouring/blended sources in all three SPIRE bands. We compare the colours with redshift tracks of various contemporary models. Based on these spectral templates we show that regions corresponding to specific population types and redshifts can be identified better in colour-flux space. The redshift tracks as well as the colour-flux plots imply a majority of detected objects with redshifts at 1 < z < 3.5, somewhat depending on the group of model SEDs used. We also find that a population of sources with S 250 /S 350 < 0.8 at fluxes above 50 mJy as observed by SPIRE are not well represented by contemporary models and could consist of a mix of cold and lensed galaxies. © 2010 ESO.


First results from HerMES on the evolution of the submillimetre luminosity function

Astronomy and Astrophysics 518 (2010)

SA Eales, G Raymond, IG Roseboom, B Altieri, A Amblard, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, D Brisbin, V Buat, D Burgarella, N Castro-Rodríguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Dye, D Elbaz, D Farrah, M Fox, A Franceschini, W Gear, J Glenn, EA González Solares, M Griffin, M Harwit, E Hatziminaoglou, J Huang, E Ibar, K Isaak, RJ Ivison, G Lagache, L Levenson, CJ Lonsdale, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, GE Morrison, AMJ Mortier, HT Nguyen, B O'Halloran, SJ Oliver, A Omont, FN Owen, MJ Page, M Pannella, P Panuzzo, A Papageorgiou, CP Pearson, I Pérez-Fournon, M Pohlen, JI Rawlings, D Rigopoulou, D Rizzo, M Rowan-Robinson, M Sánchez Portal, B Schulz, D Scott, N Seymour, DL Shupe, AJ Smith, JA Stevens, V Strazzullo, M Symeonidis, M Trichas, KE Tugwell, M Vaccari, I Valtchanov, L Vigroux, L Wang, R Ward, G Wright, CK Xu

We have carried out two extremely deep surveys with SPIRE, one of the two cameras on Herschel, at 250 μm, close to the peak of the far-infrared background. We have used the results to investigate the evolution of the rest-frame 250-μm luminosity function out to z = 2. We find evidence for strong evolution out to z $\simeq$ 1 but evidence for at most weak evolution beyond this redshift. Our results suggest that a significant part of the stars and metals in the universe today were formed at z 1.4 in spiral galaxies. © 2010 ESO.


Cold dust and young starbursts: Spectral energy distributions of Herschel SPIRE sources from the HerMES survey

Monthly Notices of the Royal Astronomical Society 409 (2010) 2-11

M Rowan-Robinson, IG Roseboom, M Vaccari, A Amblard, V Arumugam, R Auld, H Aussel, T Babbedge, A Blain, J Bock, A Boselli, D Brisbin, V Buat, D Burgarella, N Castro-Rodriguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Dye, S Eales, D Elbaz, D Farrah, M Fox, A Franceschini, W Gear, J Glenn, EAG Solares, M Griffin, M Halpern, E Hatziminaoglou, J Huang, E Ibar, K Isaak, RJ Ivison, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, AMJ Mortier, HT Nguyen, B O'Halloran, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, H Patel, CP Pearson, IP Fournon, M Pohlen, JI Rawlings, G Raymond, D Rigopoulou, D Rizzo, B Schulz, D Scott, N Seymour, DL Shupe, AJ Smith, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, I Valtchanov, L Vigroux, L Wang, R Ward, G Wright, CK Xu, M Zemcov

We present spectral energy distributions (SEDs) for 68 Herschel sources detected at 5σ at 250, 350 and 500 μm in the HerMES SWIRE-Lockman field. We explore whether existing models for starbursts, quiescent star-forming galaxies and active galactic nucleus dust tori are able to model the full range of SEDs measured with Herschel. We find that while many galaxies ( 56 per cent) are well fitted with the templates used to fit IRAS, Infrared Space Observatory (ISO) and Spitzer sources, for about half the galaxies two new templates are required: quiescent ('cirrus') models with colder (10-20 K) dust and a young starburst model with higher optical depth than Arp 220. Predictions of submillimetre fluxes based on model fits to 4.5-24 μm data agree rather poorly with the observed fluxes, but the agreement is better for fits to 4.5-70 μm data. Herschel galaxies detected at 500 μm tend to be those with the highest dust masses. © 2010 The Authors. Journal compilation © 2010 RAS.


On the stellar masses of IRAC detected Lyman Break Galaxies at z similar to 3

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 401 (2010) 1521-1531

GE Magdis, D Rigopoulou, J-S Huang, GG Fazio


Herschel-ATLAS: Evolution of the 250 μm luminosity function out to z = 0.5

Astronomy and Astrophysics 518 (2010)

S Dye, L Dunne, S Eales, DJB Smith, A Amblard, R Auld, M Baes, IK Baldry, S Bamford, AW Blain, DG Bonfield, M Bremer, D Burgarella, S Buttiglione, E Cameron, A Cava, DL Clements, A Cooray, S Croom, A Dariush, G De Zotti, S Driver, JS Dunlop, D Frayer, J Fritz, JP Gardner, HL Gomez, J Gonzalez-Nuevo, D Herranz, D Hill, A Hopkins, E Ibar, RJ Ivison, MJ Jarvis, DH Jones, L Kelvin, G Lagache, L Leeuw, J Liske, M Lopez-Caniego, J Loveday, S Maddox, MJ Michałowski, M Negrello, P Norberg, MJ Page, H Parkinson, E Pascale, JA Peacock, M Pohlen, C Popescu, M Prescott, D Rigopoulou, A Robotham, E Rigby, G Rodighiero, S Samui, D Scott, S Serjeant, R Sharp, B Sibthorpe, P Temi, MA Thompson, R Tuffs, I Valtchanov, PP Van Der Werf, E Van Kampen, A Verma

We have determined the luminosity function of 250 μm-selected galaxies detected in the ∼14 deg2science demonstration region of the Herschel-ATLAS project out to a redshift of z = 0.5. Our findings very clearly show that the luminosity function evolves steadily out to this redshift. By selecting a sub-group of sources within a fixed luminosity interval where incompleteness effects are minimal, we have measured a smooth increase in the comoving 250 μm luminosity density out to z = 0.2 where it is 3.6+1.4-0.9times higher than the local value. © 2010 ESO.


A MULTI-WAVELENGTH VIEW OF THE STAR FORMATION ACTIVITY AT z similar to 3

ASTROPHYSICAL JOURNAL 714 (2010) 1740-1745

GE Magdis, D Elbaz, E Daddi, GE Morrison, M Dickinson, D Rigopoulou, R Gobat, HS Hwang


HerMES: Herschel-SPIRE observations of Lyman break galaxies

Monthly Notices of the Royal Astronomical Society: Letters 409 (2010)

D Rigopoulou, G Magdis, RJ Ivison, A Amblard, V Arumugam, H Aussel, A Blain, J Bock, A Boselli, V Buat, D Burgarella, N Castro-Rodríguez, A Cava, P Chanial, DL Clements, A Conley, L Conversi, A Cooray, CD Dowell, E Dwek, S Eales, D Elbaz, D Farrah, A Franceschini, J Glenn, M Griffin, M Halpern, E Hatziminaoglou, JS Huang, E Ibar, K Isaak, G Lagache, L Levenson, N Lu, S Madden, B Maffei, G Mainetti, L Marchetti, HT Nguyen, B O'Halloran, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Pérez-Fournon, M Pohlen, D Rizzo, IG Roseboom, M Rowan-Robinson, B Schulz, D Scott, N Seymour, DL Shupe, AJ Smith, JA Stevens, M Symeonidis, M Trichas, KE Tugwell, M Vaccari, I Valtchanov, L Vigroux, L Wang, G Wright, CK Xu, M Zemcov

We present first results of a study of the submillimetre (submm) (rest-frame far-infrared) properties of z ~ 3 Lyman break galaxies (LBGs) and their lower redshift counterparts BX/BM galaxies, based on Herschel-SPIRE observations of the Northern field of the Great Observatories Origins Deep Survey (GOODS-N). We use stacking analysis to determine the properties of LBGs well below the current limit of the survey. Although LBGs are not detected individually, stacking the infrared luminous LBGs (those detected with Spitzer at 24 |xm) yields a statistically significant submm detection with mean flux 〈S 250 〉 = 5.9 ±1.4 mJy confirming the power of SPIRE in detecting UV-selected high-redshift galaxies at submm wavelengths. In comparison, the Spitzer 24 |j.m detected BX/BM galaxies appear fainter with a stacked value of 〈S 250 〉 = 2.7 ± 0.8 mJy. By fitting the spectral energy distributions (SEDs) we derive median infrared luminosities, L IR , of 2.8 × 10 12 L ⊙ and 1.5 × 10 11 L. for z ~ 3 LBGs and BX/BMs, respectively. We find that LIR estimates derived from present measurements are in good agreement with those based on UV data for z ~ 2 BX/BM galaxies, unlike the case for z ~ 3 infrared luminous LBGs where the UV underestimates the true LIR. Although sample selection effects may influence this result we suggest that differences in physical properties (such as morphologies, dust distribution and extent of star-forming regions) between z ~ 3 LBGs and z ~ 2 BX/BMs may also play a significant role. © 2010 The Authors. Journal compilation © 2010 RAS.


HerMES: SPIRE detection of high-redshift massive compact galaxies in GOODS-N field

Monthly Notices of the Royal Astronomical Society: Letters 409 (2010)

A Cava, G Rodighiero, I Pérez-Fournon, F Buitrago, I Trujillo, B Altieri, A Amblard, R Auld, J Bock, D Brisbin, D Burgarella, N Castro-Rodríguez, P Chanial, M Cirasuolo, DL Clements, CJ Conselice, A Cooray, S Eales, D Elbaz, P Ferrero, A Franceschini, J Glenn, EG González Solares, M Griffin, E Ibar, RJ Ivison, L Marchetti, GE Morrison, AMJ Mortier, SJ Oliver, MJ Page, A Papageorgiou, CP Pearson, M Pohlen, JI Rawlings, G Raymond, D Rigopoulou, IG Roseboom, M Rowan-Robinson, D Scott, N Seymour, AJ Smith, M Symeonidis, KE Tugwell, M Vaccari, I Valtchanov, JD Vieira, L Vigroux, L Wang, G Wright

Wehave analysed the rest-frame far-infrared properties ofa sample of massive (M * > 10 11 M ⊙ ) galaxies at 2 ≲ z ≲ 3 in the Great Observatories Origins Deep Survey-North (GOODS-N) field using the Spectral and Photometric Imaging Receiver (SPIRE) instrument aboard the Herschel Space Observatory. To conduct this analysis we take advantage of the data from the Herschel Multi-tiered Extragalactic Survey (HerMES) key programme. The sample comprises 45 massive galaxies with structural parameters characterized with HST NICMOS-3. We study detections at submm Herschel bands, together with Spitzer 24-μm data, as a function of the morphological type, mass and size. We find that 26/45 sources are detected at MIPS 24 μm and 15/45 (all MIPS 24-μm detections) are detected at SPIRE 250 μ with disc-like galaxies more easily detected. We derive star formation rates (SFRs) and specific star formation rates (sSFRs) by fitting the spectral energy distribution of our sources, taking into account non-detections for SPIRE and systematic effects for MIPS derived quantities. We find that the mean SFR for the spheroidal galaxies (~50-100M ⊙ yr -1 ) is substantially (a factor ~3) lower than the mean value presented by disc-like galaxies (~250-300M ⊙ yr -1 ). © 2010 The Authors. Journal compilation © 2010 RAS.


Herschel unveils a puzzling uniformity of distant dusty galaxies

Astronomy and Astrophysics 518 (2010)

D Elbaz, HS Hwang, B Magnelli, E Daddi, H Aussel, B Altieri, A Amblard, P Andreani, V Arumugam, R Auld, T Babbedge, S Berta, A Blain, J Bock, A Bongiovanni, A Boselli, V Buat, D Burgarella, N Castro-Rodriguez, A Cava, J Cepa, P Chanial, RR Chary, A Cimatti, DL Clements, A Conley, L Conversi, A Cooray, M Dickinson, H Dominguez, CD Dowell, JS Dunlop, E Dwek, S Eales, D Farrah, N Förster Schreiber, M Fox, A Franceschini, W Gear, R Genzel, J Glenn, M Griffin, C Gruppioni, M Halpern, E Hatziminaoglou, E Ibar, K Isaak, RJ Ivison, G Lagache, D Le Borgne, E Le Floc'H, L Levenson, N Lu, D Lutz, S Madden, B Maffei, G Magdis, G Mainetti, R Maiolino, L Marchetti, AMJ Mortier, HT Nguyen, R Nordon, B O'Halloran, K Okumura, SJ Oliver, A Omont, MJ Page, P Panuzzo, A Papageorgiou, CP Pearson, I Perez Fournon, AM Pérez García, A Poglitsch, M Pohlen, P Popesso, F Pozzi, JI Rawlings, D Rigopoulou, L Riguccini, D Rizzo, G Rodighiero, IG Roseboom, M Rowan-Robinson, A Saintonge, M Sanchez Portal, P Santini, M Sauvage, B Schulz, D Scott, N Seymour, L Shao, DL Shupe, AJ Smith, JA Stevens, E Sturm, M Symeonidis, L Tacconi, M Trichas, KE Tugwell

The Herschel Space Observatory enables us to accurately measure the bolometric output of starburst galaxies and active galactic nuclei (AGN) by directly sampling the peak of their far-infrared (IR) emission. Here we examine whether the spectral energy distribution (SED) and dust temperature of galaxies have strongly evolved over the last 80% of the age of the Universe. We discuss possible consequences for the determination of starformation rates (SFR) and any evidence for a major change in their star-formation properties. We use Herschel deep extragalactic surveys from 100 to 500 μ m to compute total IR luminosities in galaxies down to the faintest levels, using PACS and SPIRE in the GOODS-North field (PEP and HerMES key programs). An extension to fainter luminosities is done by stacking images on 24 μ m prior positions. We show that measurements in the SPIRE bands can be used below the statistical confusion limit if information at higher spatial resolution is used, e.g. at 24 μ m, to identify "isolated" galaxies whose flux is not boosted by bright neighbors. Below z ∼ 1.5, mid-IR extrapolations are correct for star-forming galaxies with a dispersion of only 40% (0.15 dex), therefore similar to z ∼ 0 galaxies, over three decades in luminosity below the regime of ultra-luminous IR galaxies (ULIRGs, L IR ≥ 10 12 L ⊙ ). This narrow distribution is puzzling when considering the range of physical processes that could have affected the SED of these galaxies. Extrapolations from only one of the 160 μ m, 250 μ m or 350 μ m bands alone tend to overestimate the total IR luminosity. This may be explained by the lack of far-IR constraints around and above ∼150 μ m (rest-frame) before Herschel on those templates. We also note that the dust temperature of luminous IR galaxies (LIRGs, L IR ≥ 10 11 L ⊙ ) around z ∼ 1 is mildly colder by 10-15% than their local analogs and up to 20% for ULIRGs at z ∼ 1.6 (using a single modified blackbody-fit to the peak far-IR emission with an emissivity index of β = 1.5). Above z = 1.5, distant galaxies are found to exhibit a substantially larger mid- over far-IR ratio, which could either result from stronger broad emission lines or warm dust continuum heated by a hidden AGN. Two thirds of the AGNs identified in the field with a measured redshift exhibit the same behavior as purely star-forming galaxies. Hence a large fraction of AGNs harbor coeval star formation at very high SFR and in conditions similar to purely star-forming galaxies. © 2010 ESO.

Pages