Publications by Dimitra Rigopoulou


Alma maging of the co (7−6) line emission in the submillimeter galaxy less 073 at z = 4.755

Astrophysical Journal American Astronomical Society 892 (2020) 145

Y Zhao, N Lu, T Diaz-Santos, Y Gao, K Xu, V Charmandaris, H Inami, D Rigopoulou, D Sanders, J Huang, Z Wang

In this paper we present our imaging observations on the CO (7−6) line and its underlying continuum emission of the young submillimeter galaxy LESS 073 at redshift 4.755, using the Atacama Large Millimeter/submillimeter Array (ALMA). At the achieved resolution of ∼1 ′′ .2 × 0 ′′ .9 (8 × 6 kpc2 ), the CO (7−6) emission is largely unresolved (with a deconvolved size of 1′′ .1(±0 ′′ .5) × 0 ′′ .9(±0 ′′ .8).), and the continuum emission is totally unresolved. The CO (7−6) line emission has an integrated flux of 0.86 ± 0.08 Jy km s−1 , and a line width of 343 ± 40 km s−1 . The continuum emission has a flux density of 0.51 mJy. By fitting the observed far-infrared (FIR) spectral energy distribution of LESS 073 with a single-temperature modified blackbody function, we obtained a dust temperature Tdust = 57.6 ± 3.5 K, 60-to-100 µm flux density ratio f60/f100 = 0.86 ± 0.08, and total infrared luminosity LIR = (5.8±0.9)×1012 L⊙. The SED-fit-based f60/f100 is consistent with those estimated from various line ratios as advocated by our earlier work, indicating that those proposed line-ratiobased method can be used to practically derive f60/f100 for high-z sources. The total molecular gas mass of LESS 073 is (3.3 ± 1.7) × 1010 M⊙, and the inferred gas depletion time is about 43 Myr.


Deceptively cold dust in the massive starburst galaxy GN20 at z~4

Astronomy & Astrophysics EDP Sciences (2020)

D Rigopoulou, F Valentino, E Daddi, D Liu, D Riechers, M Sargent, D Cormier, JA Hodge, M Béthermin, V Kokorev, TR Greve, F Walter, D Elbaz, S Toft, GE Magdis, I Cortzen


Review: Far-infrared instrumentation and technological development for the next decade

Journal of Astronomical Telescopes, Instruments, and Systems 5 (2019)

D Farrah, KE Smith, D Ardila, CM Bradford, M Dipirro, C Ferkinhoff, J Glenn, P Goldsmith, D Leisawitz, T Nikola, N Rangwala, SA Rinehart, J Staguhn, M Zemcov, J Zmuidzinas, J Bartlett, S Carey, WJ Fischer, J Kamenetzky, J Kartaltepe, M Lacy, DC Lis, L Locke, LR Enrique, M MacGregor, E Mills, SH Moseley, EJ Murphy, A Rhodes, M Richter, D Rigopoulou, D Sanders, R Sankrit, G Savini, S John-David, S Stierwalt

© Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Far-infrared astronomy has advanced rapidly since its inception in the late 1950s, driven by a maturing technology base and an expanding community of researchers. This advancement has shown that observations at far-infrared wavelengths are important in nearly all areas of astrophysics, from the search for habitable planets and the origin of life to the earliest stages of galaxy assembly in the first few hundred million years of cosmic history. The combination of a still-developing portfolio of technologies, particularly in the field of detectors, and a widening ensemble of platforms within which these technologies can be deployed, means that farinfrared astronomy holds the potential for paradigm-shifting advances over the next decade. We examine the current and future far-infrared observing platforms, including ground-based, suborbital, and space-based facilities, and discuss the technology development pathways that will enable and enhance these platforms to best address the challenges facing far-infrared astronomy in the 21st century.


Nuclear molecular outflow in the Seyfert galaxy NGC 3227

Astronomy and Astrophysics EDP Sciences 628 (2019) A65

A Alonso Herrero, S García-Burillo, M Pereira-Santaella, RI Davies, F Combes, M Vestergaard, SI Raimundo, A Bunker, T Díaz-Santos, P Gandhi, I García-Bernete, EKS Hicks, SF Hönig, LK Hunt, M Imanishi, T Izumi, NA Levenson, W Maciejewski1, C Packham, C Ramos Almeida, C Ricci, D Rigopoulou, P Roche, D Rosario, M Schartmann

ALMA observations have revealed nuclear dusty molecular disks or tori with characteristic sizes 15−40 pc in the few Seyferts and low -luminosity AGN that have been studied so far. These structures are generally decoupled both morphologically and kinematically from the host galaxy disk. We present ALMA observations of the CO(2–1) and CO(3–2) molecular gas transitions and associated (sub-) millimeter continua of the nearby Seyfert 1.5 galaxy NGC 3227 with angular resolutions 0.085 − 0.21″ (7–15 pc). On large scales, the cold molecular gas shows circular motions as well as streaming motions on scales of a few hundred parsecs that are associated with a large-scale bar. We fit the nuclear ALMA 1.3 mm emission with an unresolved component and an extended component. The 850 μm emission shows at least two extended components, one along the major axis of the nuclear disk, and the other along the axis of the ionization cone. The molecular gas in the central region (1″ ∼ 73 pc) shows several CO clumps with complex kinematics that appears to be dominated by noncircular motions. While we cannot conclusively demonstrate the presence of a warped nuclear disk, we also detected noncircular motions along the kinematic minor axis. They reach line-of-sight velocities of v − vsys = 150 − 200 km s−1. Assuming that the radial motions are in the plane of the galaxy, we interpret them as a nuclear molecular outflow due to molecular gas in the host galaxy that is entrained by the AGN wind. We derive molecular outflow rates of 5 M⊙ yr−1 and 0.6 M⊙ yr−1 at projected distances of up to 30 pc to the northeast and southwest of the AGN, respectively. At the AGN location we estimate a mass in molecular gas of 5 × 105 M⊙ and an equivalent average column density N(H2) = 2 − 3 × 1023 cm−2 in the inner 15 pc. The nuclear CO(2–1) and CO(3–2) molecular gas and submillimeter continuum emission of NGC 3227 do not resemble the classical compact torus. Rather, these emissions extend for several tens of parsecs and appear connected with the circumnuclear ring in the host galaxy disk, as found in other local AGN.


Discovery of a giant and luminous Lyalpha+CIV+HeII nebula at z=3.326 with extreme emission line ratios

Astronomy and Astrophysics EDP Sciences 629 (2019) A23

R Marques-Chaves, I Pérez-Fournon, M Villar-Martín, R Gavazzi, D Riechers, D Rigopoulou, J Wardlow, A Cabrera-Lavers, DL Clements, L Colina, A Cooray, D Farrah, RJ Ivison, C Jiménez-Ángel, P Martínez-Navajas, H Nayyeri, S Oliver, A Omont, D Scott, Y Shu


[CI](1-0) and [CI](2-1) in Resolved Local Galaxies

ASTROPHYSICAL JOURNAL 887 (2019) ARTN 105

CD Wilson, BT Draine, M Wolfire, J-DT Smith, L Armus, R Herrera-Camus, DA Dale, B Groves, E Brinks, D Rigopoulou, P van der Werf, E Rosolowsky, RC Kennicutt, K Sandstrom, EJ Murphy, LK Hunt, E Schinnerer, AF Crocker, E Pellegrini

© 2019. The American Astronomical Society. All rights reserved. We present resolved [C i] line intensities of 18 nearby galaxies observed with the SPIRE FTS spectrometer on the Herschel Space Observatory. We use these data along with resolved CO line intensities from J up = 1 to 7 to interpret what phase of the interstellar medium the [C i] lines trace within typical local galaxies. A tight, linear relation is found between the intensities of the CO(4-3) and [C i](2-1) lines; we hypothesize this is due to the similar upper level temperature of these two lines. We modeled the [C i] and CO line emission using large-velocity gradient models combined with an empirical template. According to this modeling, the [C i](1-0) line is clearly dominated by the low-excitation component. We determine [C i] to molecular mass conversion factors for both the [C i](1-0) and [C i](2-1) lines, with mean values of α [C i](1-0) = 7.3 M o K-1 km-1 s pc-2 and α [C i](2-1) = 34 M o K-1 km-1 s pc-2 with logarithmic root-mean-square spreads of 0.20 and 0.32 dex, respectively. The similar spread of α [C I](1-0) to αCO (derived using the CO(2-1) line) suggests that [C i](1-0) may be just as good a tracer of cold molecular gas as CO(2-1) in galaxies of this type. On the other hand, the wider spread of α [C i](2-1) and the tight relation found between [C i](2-1) and CO(4-3) suggest that much of the [C i](2-1) emission may originate in warmer molecular gas.


Optical integral field spectroscopy of intermediate redshift infrared bright galaxies

Monthly Notices of the Royal Astronomical Societ Oxford University Press 486 (2019) 5621–5645-

M Pereira-Santaella, D Rigopoulou, GE Magdis, N Thatte, A Alonso-Herrero, F Clarke, D Farrah, S García-Burillo, L Hogan, S Morris, M Rodrigues, J-S Huang, M Tecza

The extreme infrared (IR) luminosity of local luminous and ultraluminous IR galaxies (U/LIRGs; 11 < logLIR/L < 12 and logLIR/L > 12, respectively) is mainly powered by star formation processes triggered by mergers or interactions. While U/LIRGs are rare locally, at z > 1, they become more common, dominate the star formation rate (SFR) density, and a fraction of them are found to be normal disc galaxies. Therefore, there must be an evolution of the mechanism triggering these intense starbursts with redshift. To investigate this evolution, we present new optical SWIFT integral field spectroscopic H α + [N II] observations of a sample of nine intermediate-z (0.2


PAHs as tracers of the molecular gas in star-forming galaxies

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 482 (2019) 1618-1633

I Cortzen, J Garrett, G Magdis, D Rigopoulou, F Valentino, M Pereira-Santaella, F Combes, A Alonso-Herrero, S Toft, E Daddi, D Elbaz, C Gomez-Guijarro, M Stockmann, J Huang, C Kramer


On the far-infrared metallicity diagnostics: applications to high-redshift galaxies

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 473 (2018) 20-29

D Rigopoulou, M Pereira-Santaella, GE Magdis, A Cooray, D Farrah, R Marques-Chaves, I Perez-Fournon, D Riechers


Extreme submillimetre starburst galaxies

ASTRONOMY & ASTROPHYSICS 619 (2018) ARTN A169

M Rowan-Robinson, L Wang, D Farrah, D Rigopoulou, C Gruppioni, M Vaccari, L Marchetti, DL Clements, WJ Pearson


The strong gravitationally lensed Herschel galaxy HLock01: Optical spectroscopy reveals a close galaxy merger with evidence of inflowing gas

Astrophysical Journal Institute of Physics 854 (2018) 151-

R Marques-Chaves, I Pérez-Fournon, R Gavazzi, PI Martínez-Navajas, D Riechers, D Rigopoulou, A Cabrera-Lavers, DL Clements, A Cooray, D Farrah, RJ Ivison, CE Jiménez-Ángel, H Nayyeri, S Oliver, A Omont, D Scott, Y Shu, J Wardlow

The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z =2.9574 ±0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total apparent magnitude mUV≃ 19.7 mag. We report here deep spectroscopic observations with the Gran Telescopio Canarias of the optically bright lensed images of HLock01. Our results suggest that HLock01 is a merger system composed of the Herschel-selected SMG and an optically bright Lyman break-like galaxy (LBG), separated by only 3.3 kpc in projection. While the SMG appears very massive (M∗≃ 5 ×1011Mo), with a highly extinguished stellar component (AV≃ 4.3), the LBG is a young, lower-mass (M∗≃ 1 ×1010Mo), but still luminous (10 × LUV∗) satellite galaxy. Detailed analysis of the high signal-to-noise ratio (S/N) rest-frame UV spectrum of the LBG shows complex kinematics of the gas, exhibiting both blueshifted and redshifted absorption components. While the blueshifted component is associated with strong galactic outflows from the massive stars in the LBG, as is common in most star-forming galaxies, the redshifted component may be associated with gas inflow seen along a favorable sightline to the LBG. We also find evidence of an extended gas reservoir around HLock01 at an impact parameter of 110 kpc, through the detection of C ii λλ1334 absorption in the red wing of a bright Lyα emitter at z ≃ 3.327. The data presented here highlight the power of gravitational lensing in high S/N studies to probe deeply into the physics of high-z star-forming galaxies.


Spatially resolved cold molecular outflows in ULIRGs

Astronomy and Astrophysics EDP Sciences 616 (2018) A171

M Pereira-Santaella, L Colina, S Garcia-Burillo, F Combes, B Emonts, S Aalto, A Alonso-Herrero, S Arribas, C Henkel, A Labiano, S Muller, JP Lopez, D Rigopoulou, PVD Werf

We present new CO(2–1) observations of three low-z (d ∼350 Mpc) ultra-luminous infrared galaxy (ULIRG) systems (six nuclei) observed with the Atacama large millimeter/submillimeter array (ALMA) at high spatial resolution (∼500 pc). We detect massive cold molecular gas outflows in five out of six nuclei (Mout ∼ (0.3 − 5) × 108 Mo). These outflows are spatially resolved with deprojected effective radii between 250 pc and 1 kpc although high-velocity molecular gas is detected up to Rmax ∼ 0.5 − 1.8 kpc (1 − 6 kpc deprojected). The mass outflow rates are 12 − 400 Mo yr−1 and the inclination corrected average velocity of the outflowing gas is 350 − 550 km s−1 (vmax = 500 − 900 km s−1 ). The origin of these outflows can be explained by the strong nuclear starbursts although the contribution of an obscured active galactic nucleus cannot be completely ruled out. The position angle (PA) of the outflowing gas along the kinematic minor axis of the nuclear molecular disk suggests that the outflow axis is perpendicular to the disk for three of these outflows. Only in one case is the outflow PA clearly not along the kinematic minor axis, which might indicate a different outflow geometry. The outflow depletion times are 15 − 80 Myr. These are comparable to, although slightly shorter than, the starformation (SF) depletion times (30 − 80 Myr). However, we estimate that only 15 − 30% of the outflowing molecular gas will escape the gravitational potential of the nucleus. The majority of the outflowing gas will return to the disk after 5 − 10 Myr and become available to form new stars. Therefore, these outflows will not likely completely quench the nuclear starbursts. These star-forming powered molecular outflows would be consistent with being driven by radiation pressure from young stars (i.e., momentum-driven) only if the coupling between radiation and dust increases with increasing SF rates. This can be achieved if the dust optical depth is higher in objects with higher SF. This is the case in at least one of the studied objects. Alternatively, if the outflows are mainly driven by supernovae (SNe), the coupling efficiency between the interstellar medium and SNe must increase with increasing SF levels. The relatively small sizes (<1 kpc) and dynamical times (<3 Myr) of the cold molecular outflows suggests that molecular gas cannot survive longer in the outflow environment or that it cannot form efficiently beyond these distances or times. In addition, the ionized and hot molecular phases have been detected for several of these outflows, so this suggests that outflowing gas can experience phase changes and indicates that the outflowing gas is intrinsically multiphase, likely sharing similar kinematics, but different mass and, therefore, different energy and momentum contributions.


Resolving the nuclear obscuring disk in the Compton-thick Seyfert galaxy NGC 5643 with ALMA

Astrophysical Journal American Astronomical Society 859 (2018) 144-

A Alonso-Herrero, M Pereira-Santaella, S Garcia-Burillo, RI Davies, F Combes, D Asmus, A Bunker, T Diaz-Santos, P Gandhi, O Gonzalez-Martin, A Hernan-Caballero, E Hicks, S Hoenig, A Labiano, NA Levenson, C Packham, CR Almeida, C Ricci, D Rigopoulou, D Rosario, E Sani, MJ Ward

We present ALMA Band 612CO(2-1) line and rest-frame 232 GHz continuum observations of the nearby Compton-thick Seyfert galaxy NGC 5643 with angular resolutions 0.″11-0.″26 (9-21 pc). The CO(2-1) integrated line map reveals emission from the nuclear and circumnuclear region with a two-arm nuclear spiral extending ∼10″ on each side. The circumnuclear CO(2-1) kinematics can be fitted with a rotating disk, although there are regions with large residual velocities and/or velocity dispersions. The CO(2-1) line profiles of these regions show two different velocity components. One is ascribed to the circular component and the other to the interaction of the AGN outflow, as traced by the [O iii]λ5007 Åemission, with molecular gas in the disk a few hundred parsecs from the AGN. On nuclear scales, we detected an inclined CO(2-1) disk (diameter 26 pc, FWHM) oriented almost in a north-south direction. The CO(2-1) nuclear kinematics can be fitted with a rotating disk that appears to be tilted with respect to the large-scale disk. There are strong non-circular motions in the central 0.″2-0.″3 with velocities of up to 110 km s-1. In the absence of a nuclear bar, these motions could be explained as radial outflows in the nuclear disk. We estimate a total molecular gas mass for the nuclear disk of M(H2) = 1.1 ×107Moand an H2column density toward the location of the AGN of N(H2) ∼ 5 ×1023cm-2, for a standard CO-to-H2conversion factor. We interpret this nuclear molecular gas disk as the obscuring torus of NGC 5643 as well as the collimating structure of the ionization cone.


HERUS: The far-IR/submm spectral energy distributions of local ULIRGs and photometric atlas

Monthly Notices of the Royal Astronomical Society Oxford University Press 475 (2017) 2097–2121-

DL Clements, C Pearson, D Farrah, J Greenslade, J Bernard-Salas, E González-Alfonso, J Afonso, A Efstathiou, D Rigopoulou, V Lebouteiller, PD Hurley, H Spoon

We present the Herschel-SPIRE photometric atlas for a complete flux limited sample of 43 local Ultraluminous Infrared Galaxies (ULIRGs), selected at 60μm by IRAS, as part of the HERschel ULIRG Survey (HERUS). Photometry observations were obtained using the SPIRE instrument at 250, 350 and 500μm. We describe these observations, present the results, and combine the new observations with data from IRAS to examine the far-IR spectral energy distributions (SEDs) of these sources. We fit the observed SEDs of HERUS objects with a simple parameterised modified black body model where temperature and emissivity β are free parameters.We compare the fitted values to those of non-ULIRG local galaxies, and find, in agreement with earlier results, that HERUS ULIRGs have warmer dust (median temperature T = 37.9±4.7 K compared to 21.3±3.4 K) but a similar β distribution (median β = 1.7 compared to 1.8) to the Herschel reference sample (HRS, Cortese et al., 2014) galaxies. Dust masses are found to be in the range of 107.5 to 109 M⊙, significantly higher than that of Herschel Reference Sample (HRS) sources.We compare our results for local ULIRGs with higher redshift samples selected at 250 and 850μm. These latter sources generally have cooler dust and/or redder 100-to-250 μm colours than our 60μm-selected ULIRGs. We show that this difference may in part be the result of the sources being selected at different wavelengths rather than being a simple indication of rapid evolution in the properties of the population.


CO (7-6), [C I] 370 μm, and [N II] 205 μm Line Emission of the QSO BRI1335-0417 at Redshift 4.407

Astrophysical Journal Institute of Physics 864 (2018) 38-

N Lu, T Cao, T Diaz-Santos, Y Zhao, GC Privon, C Cheng, Y Gao, CK Xu, V Charmandaris, D Rigopoulou, PP Van Der Werf, J Huang, Z Wang, AS Evans, DB Sanders

We present the results from our Atacama Large Millimeter/submillimeter Array (ALMA) imaging observations of the CO(7-6), [C i] 370 μm (hereafter [C i]), and [N ii] 205 μm (hereafter [N ii]) lines and their underlying continuum emission of BRI 1335-0417, an infrared bright quasar at z = 4.407. At the achieved resolutions of ∼1.″1 to 1.″2 (or 7.5-8.2 kpc), the continuum at 205 and 372 μm (rest frame), the CO(7-6), and the [C i] emissions are at best barely resolved whereas the [N ii] emission is well resolved with a beam-deconvolved major axis of 1.″3(±0.″3) or 9(±2) kpc. As a warm dense gas tracer, the CO(7-6) emission shows a more compact spatial distribution and a significantly higher peak velocity dispersion than the other two lines that probe lower density gas, a picture favoring a merger-Triggered star formation (SF) scenario over an orderly rotating SF disk. The CO(7-6) data also indicate a possible QSO-driven gas outflow that reaches a maximum line-of-sight velocity of 500-600 km s-1. The far-infrared (FIR) dust temperature (Tdust) of 41.5 K from a graybody fit to the continuum agrees well with the average Tdustinferred from various line luminosity ratios. The resulting LCO(7-6)/LFIRluminosity ratio is consistent with that of local luminous infrared galaxies powered predominantly by SF. The LCO(7-6)-inferred SF rate is 5.1(±1.5) × 103Moyr-1. The system has an effective star-forming region of kpc in diameter and a molecular gas reservoir of ∼5 × 1011Mo.


The MALATANG survey: The L GAS–L IR correlation on sub-kiloparsec scale in six nearby star-forming galaxies as traced by HCN J = 4 → 3 and HCO+ J = 4 → 3

Astrophysical Journal Institute of Physics 860 (2018) 165-

Q-H Tan, Y Gao, Z-Y Zhang, TR Greve, X-J Jiang, CD Wilson, C-T Yang, A Bemis, A Chung, S Matsushita, Y Shi, Y-P Ao, E Brinks, MJ Currie, TA Davis, RD Grijs, LC Ho, M Imanishi, K Kohno, B Lee, H Parsons, D Rigopoulou, J Bulger, H Chen

We present HCN J = 4→3 and HCO+ J = 4→3 maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2×2 region at 14 (FWHM) resolution (corresponding to linear scales of ∼0.2-1.0 kpc). The LIR-Ldense relation, where the dense gas is traced by the HCN J = 4→3 and the HCO+ J = 4→3 emission, measured in our sample of spatially resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, LIR/Ldense, shows systematic variations with LIR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between LIR/Ldense ratio and the warm-dust temperature gauged by the 70 μm/100 μm flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO+ (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas (SFEdense), appear to be nearly independent of the dense gas fraction ( fdense) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with fdensewhen combining our data with those on local (ultra)luminous infrared galaxies and high-z quasars. The mean LHCN(4-3) LHCO+(4-3) line ratio measured for the six targeted galaxies is 0.9±0.6. No significant correlation is found for the L'HCN(4-3) L'HCO+(4-3) ratio with the star formation rate as traced by LIR, nor with the warm-dust temperature, for the different populations of galaxies.


Dust and gas in star-forming galaxies at z ~ 3: Extending galaxy uniformity to 11.5 billion years

Astronomy & Astrophysics EDP Sciences 603 (2017) A93-

GE Magdis, D Rigopoulou, E Daddi, M Bethermin, C Feruglio, M Sargent, H Dannerbauer, M Dickinson, D Elbaz, C Gomez Guijarro, J-S Huang, S Toft, F Valentino

We present millimetre dust emission measurements of two Lyman-break galaxies at z ∼ 3 and construct for the first time fully sampled infrared spectral energy distributions (SEDs), from mid-IR to the Rayleigh-Jeans tail, of individually detected, unlensed, UV-selected, main sequence (MS) galaxies at z = 3. The SED modelling of the two sources confirms previous findings, based on stacked ensembles, of an increasing mean radiation field (U) with redshift, consistent with a rapidly decreasing gas metallicity in z > 2 galaxies. Complementing our study with CO[J = 3 → 2] emission line observations, we have measured the molecular gas mass reservoir (M H 2 ) of the systems using three independent approaches: 1) CO line observations; 2) the dust to gas mass ratio vs. metallicity relation; and 3) a single band, dust emission flux on the Rayleigh-Jeans side of the SED. All techniques return consistent M H 2 estimates within a factor of two or less, yielding gas depletion time-scales (τ dep ≈ 0.35 Gyr) and gas-to-stellar mass ratios (M H 2 /M ∗ ≈ 0.5-1) for our z ∼ 3 massive MS galaxies. The overall properties of our galaxies are consistent with trends and relations established at lower redshifts, extending the apparent uniformity of star-forming galaxies over the last 11.5 billion years.


Rise of the Titans: A dusty, hyper-luminous "870 micron riser" galaxy at z~6

Astrophysical Journal Institute of Physics 850 (2017) 1-

DA Riechers, TKD Leung, RJ Ivison, I Perez-Fournon, AJR Lewis, R Marques-Chaves, I Oteo, DL Clements, A Cooray, J Greenslade, P Martinez-Navajas, S Oliver, D Rigopoulou, D Scott, A Weiss

We report the detection of ADFS-27, a dusty, starbursting major merger at a redshift of z=5.655, using the Atacama Large Millimeter/submillimeter Array (ALMA). ADFS-27 was selected from Herschel/SPIRE and APEX/LABOCA data as an extremely red "870 micron riser" (i.e., S_250<s_350<s_500<s_870), "maximum="" 1.8="" 2.1="" 3mm="" 750msun="" 870="" 9.0="" a="" alma="" also="" an="" and="" at="" atmospheric="" billion="" binary="" by="" co="" co(5-4)="" co(6-5)="" comparable="" components,="" consistent="" continuum="" cosmic="" demonstrating="" densities="" density="" detection="" detections="" diameter,="" discovery="" distant="" dust="" dusty="" easing="" emission="" emission,="" first="" for="" formation="" galaxies="" galaxies.="" galaxy,="" gas="" h2o(211-202)="" higher="" highest-redshift="" hyper-luminous="" identify="" implies="" in="" infrared="" into="" is="" its="" kind="" known.="" kpc="" kpc,="" kpc2,="" l_ir~="2.4x10^13Lsun" large="" least="" lines="" luminosities,="" luminosity="" luminous="" m_gas="2.5x10^11(alpha_CO/0.8)(0.39/r_51)" maintain="" major="" mass="" massive="" measurement.="" merger.="" micron="" molecular="" most="" msun="" msun,="" myr.="" of="" ongoing="" presently="" previously="" provides="" quasars="" quiescent="" rare="" rate="" redshift="" regarding="" represents="" reservoir="" resolved="" scan="" separated="" sigma_sfr="730" significantly="" some="" space="" star="" starburst="" starburst".="" starbursts="" strength="" sufficient="" suggesting="" surface="" system="" technique="" tensions="" tentative="" than="" that="" the="" this="" thought="" time,="" to="" two="" unambiguous="" utility="" which="" window="" with="" within="" years="" yields="" yr="" z="" z~6="" ~100="" ~2400="">~3.</s_350<s_500<s_870),>


Stacked Average Far-infrared Spectrum of Dusty Star-forming Galaxies from the Herschel/SPIRE Fourier Transform Spectrometer

ASTROPHYSICAL JOURNAL 848 (2017) ARTN 30

D Wilson, A Cooray, H Nayyeri, M Bonato, CM Bradford, DL Clements, G De Zotti, T Diaz-Santos, D Farrah, G Magdis, MJ Michalowski, C Pearson, D Rigopoulou, I Valtchanov, L Wang, J Wardlow


The origins of [C ii] emission in local star-forming galaxies

Astrophysical Journal Institute of Physics 845 (2017)

KV Croxall, JD Smith, E Pellegrini, B Groves, A Bolatto, R Herrera-Camus, KM Sandstrom, B Draine, Wolfire, L Armus, M Boquien, B Brandl, D Dale, M Galametz, L Hunt, R Kennicutt, K Kreckel, D Rigopoulou, PVD Werf, C Wilson

The [C II] 158 μm fine-structure line is the brightest emission line observed in local star-forming galaxies. As a major coolant of the gas-phase interstellar medium, [C II] balances the heating, including that due to far-ultraviolet photons, which heat the gas via the photoelectric effect. However, the origin of [C II] emission remains unclear because C+ can be found in multiple phases of the interstellar medium. Here we measure the fractions of [C II] emission originating in the ionized and neutral gas phases of a sample of nearby galaxies. We use the [N II] 205 μm fine-structure line to trace the ionized medium, thereby eliminating the strong density dependence that exists in the ratio of [C II]/[N II] 122 μm. Using the FIR [C II] and [N II] emission detected by the KINGFISH (Key Insights on Nearby Galaxies: a Far- Infrared Survey with Herschel) and Beyond the Peak Herschel programs, we show that 60%–80% of [C II] emission originates from neutral gas. We find that the fraction of [C II] originating in the neutral medium has a weak dependence on dust temperature and the surface density of star formation, and has a stronger dependence on the gas-phase metallicity. In metal-rich environments, the relatively cooler ionized gas makes substantially larger contributions to total [C II] emission than at low abundance, contrary to prior expectations. Approximate calibrations of this metallicity trend are provided.

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