Publications


High resolution imaging of the magnetic field in the central parsec of the Galaxy

Planetary and Space Science Elsevier (2018)

P Roche, E Lopez Rodriguez, CM Telesco, R Schodel, C Packham

We discuss a high resolution (FWHM∼ 0:45 arcsec) image of the emissive polarization from warm dust in the minispiral in the Galactic Centre and discuss the implications for the magnetic field in the dusty filaments. The image was obtained at a wavelength of 12.5 μm with the CanariCam multimode mid-infrared imager on the Gran Telescopio Canarias. It confirms the results obtained from previous observations but also reveals new details of the polarization structures. In particular, we identify regions of coherent magnetic field emission at position angles of ∼ 45o to the predominantly north–south run of field lines in the Northern Arm which may be related to orbital motions inclined to the general flow of the Northern Arm. The luminous stars that have been identified as bow-shock sources in the Northern Arm do not disrupt or dilute the field but are linked by a coherent field structure, implying that the winds from these objects may push and compress the field but do not overwhelm it. The magnetic field in the low surface brightness regions in the East-West Bar to the south of SgrA* lies along the Bar, but the brighter regions generally have different polarization position angles, suggesting that they are distinct structures. In the region of the Northern Arm sampled here, there is only a weak correlation between the intensity of the emission and the degree of polarization. This is consistent with saturated grain alignment where the degree of polarization depends on geometric effects, including the angle of inclination of the field to the line of sight and superposition of filaments with different field directions, rather than the alignment efficiency.


A few StePS forward in unveiling the complexity of galaxy evolution: light-weighted stellar ages of intermediate-redshift galaxies with WEAVE

Astronomy and Astrophysics EDP Sciences 632 (2019) A9

L Costantin, A Iovino, S Zibetti, M Longhetti, A Gallazzi, A Mercurio, I Lonoce, M Balcells, M Bolzonella, G Busarello, G Dalton, A Ferre-Mateu, R Garcia-Benito, S Jin, F La Barbera, P Merluzzi, DNA Murphy, PDAL de Arriba, P Sanchez-Blazquez, M Talia, C Tortora, SC Trager, A Vazdekis, D Vergani, B Vulcani

<br><strong><i>Context. </strong></i>The upcoming new generation of optical spectrographs on four-meter-class telescopes, with their huge multiplexing capabilities, excellent spectral resolution, and unprecedented wavelength coverage, will provide invaluable information for reconstructing the history of star formation in individual galaxies up to redshifts of about 0.7.</br> <br><strong><i>Aims. </strong></i>We aim at defining simple but robust and meaningful physical parameters that can be used to trace the coexistence of widely diverse stellar components: younger stellar populations superimposed on the bulk of older ones.</br> <br><strong><i>Methods. </strong></i>We produced spectra of galaxies closely mimicking data from the forthcoming Stellar Populations at intermediate redshifts Survey (StePS), a survey that uses the WEAVE spectrograph on the William Herschel Telescope. First, we assessed our ability to reliably measure both ultraviolet and optical spectral indices in galaxies of different spectral types for typically expected signal-to-noise ratios. We then analyzed such mock spectra with a Bayesian approach, deriving the probability density function of r- and u-band light-weighted ages as well as of their difference.</br> <br><strong><i>Results. </strong></i>We find that the ultraviolet indices significantly narrow the uncertainties in estimating the r- and u-band light-weighted ages and their difference in individual galaxies. These diagnostics, robustly retrievable for large galaxy samples even when observed at moderate signal-to-noise ratios, allow us to identify secondary episodes of star formation up to an age of ∼0.1 Gyr for stellar populations older than ∼1.5 Gyr, pushing up to an age of ∼1 Gyr for stellar populations older than ∼5 Gyr.</br> <br><strong><i>Conclusions. </strong></i>The difference between r-band and u-band light-weighted ages is shown to be a powerful diagnostic to characterize and constrain extended star-formation histories and the presence of young stellar populations on top of older ones. This parameter can be used to explore the interplay between different galaxy star-formation histories and physical parameters such as galaxy mass, size, morphology, and environment.</br>


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.


Optical integral field spectroscopy of intermediate redshift infrared bright galaxies

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) (0)

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 ultra-luminous IR galaxies (U/LIRGs; 11 < log LIR /Lsun < 12 and log LIR /Lsun > 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, they dominate the star-formation rate (SFR) density, and a fraction of them are found to be normal disk 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{\alpha}+[NII] observations of a sample of 9 intermediate-z (0.2 < z < 0.4) U/LIRG systems selected from Herschel 250{\mu}m observations. The main results are the following: (a) the ratios between the velocity dispersion and the rotation curve amplitude indicate that 10-25% (1-2 out of 8) might be compatible with being isolated disks while the remaining objects are interacting/merging systems; (b) the ratio between un-obscured and obscured SFR traced by H{\alpha} and LIR, respectively, is similar in both local and these intermediate-z U/LIRGs; and (c) the ratio between 250{\mu}m and the total IR luminosities of these intermediate-z U/LIRGs is higher than that of local U/LIRGs with the same LIR . This indicates a reduced dust temperature in these intermediate-z U/LIRGs. This, together with their already measured enhanced molecular gas content, suggests that the interstellar medium conditions are different in our sample of intermediate-z galaxies when compared to local U/LIRGs.


On the Observed Diversity of Star Formation Efficiencies in Giant Molecular Clouds

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 468 (2019) 5482-5491

K Grisdale, O Agertz, F Renaud, AB Romeo, J Devriendt, A Slyz

Observations find a median star formation efficiency per free-fall time in Milky Way Giant Molecular Clouds (GMCs) on the order of $\epsilon_{\rm ff}\sim 1\%$ with dispersions of $\sim0.5\,{\rm dex}$. The origin of this scatter in $\epsilon_{\rm ff}$ is still debated and difficult to reproduce with analytical models. We track the formation, evolution and destruction of GMCs in a hydrodynamical simulation of a Milky Way-like galaxy and by deriving cloud properties in an observationally motivated way, measure the distribution of star formation efficiencies which are in excellent agreement with observations. We find no significant link between $\epsilon_{\rm ff}$ and any measured global property of GMCs (e.g. gas mass, velocity dispersion). Instead, a wide range of efficiencies exist in the entire parameter space. From the cloud evolutionary tracks, we find that each cloud follow a \emph{unique} evolutionary path which gives rise to wide diversity in all properties. We argue that it is this diversity in cloud properties, above all else, that results in the dispersion of $\epsilon_{\rm ff}$.


Black Hole-Galaxy Scaling Relation Evolution From z~2.5: Simulated Observations With HARMONI on the ELT

Frontiers in Astronomy and Space Sciences 6 (2019)

B García-Lorenzo, A Monreal-Ibero, E Mediavilla, M Pereira-Santaella, N Thatte

© Copyright © 2019 García-Lorenzo, Monreal-Ibero, Mediavilla, Pereira-Santaella and Thatte. We present preliminary results on the potential of HARMONI, the first light integral field spectrograph for the ELT, to explore the evolution of central super massive black holes (SMBH)—host galaxy relation in the range from z~0.7 to z~2.5. We simulated HARMONI observations of QSO+host galaxy at different redshifts, assuming different morphologies for the host galaxy. As input, we combined MUSE observations of nearby galaxies and a theoretical QSO spectrum. These were dimmed and redshifted to the desired cosmic epoch. We scaled the total host galaxy luminosity to three different values, sampling three orders of magnitude. Likewise, we assumed two different luminosities for the central QSO. Simulations were performed for the 30×60 mas2 HARMONI spatial scale and LTAO working at 0.67 arcsec seeing. The selected wavelength range (i.e., 4,700–5,300 Å at rest-frame) was sampled at the lowest HARMONI spectral resolving power (i.e., R~3,200). This configuration included all the ingredients to estimate the host galaxy parameters and the SMBH mass, as well as for assessing the morphological type of the host galaxy.


Emission from the circumgalactic medium: from cosmological zoom-in simulations to multiwavelength observables

Monthly Notices of the Royal Astronomical Society Oxford University Press 489 (2019) 2417–2438-

R Augustin, S Quiret, B Milliard, C Peroux, D Vibert, J Blaizot, Y Rasera, R Teyssier, S Frank, J-M Deharveng, V Picouet, DC Martin, ET Hamden, N Thatte, MP Santaella, L Routledge, S Zieleniewski

<p>We simulate the flux emitted from galaxy haloes in order to quantify the brightness of the circumgalactic medium (CGM). We use dedicated zoom-in cosmological simulations with the hydrodynamical adaptive mesh refinement code RAMSES, which are evolved down to <em>z</em> = 0 and reach a maximum spatial resolution of 380 <em>h</em><sup>−1</sup> pc and a gas mass resolution up to 1.8×10<sup>5</sup> h<sup>−</sup><sup>1</sup> M⊙ in the densest regions. We compute the expected emission from the gas in the CGM using CLOUDY emissivity models for different lines (e.g. Lyα, C IV, O VI, C VI, O VIII) considering UV background fluorescence, gravitational cooling and continuum emission. In the case of Lyα, we additionally consider the scattering of continuum photons. We compare our predictions to current observations and find them to be in good agreement at any redshift after adjusting the Lyα escape fraction. We combine our mock observations with instrument models for Faint Intergalactic Redshifted Emission Balloon-2 (FIREBall-2; UV balloon spectrograph) and HARMONI (visible and NIR IFU on the ELT) to predict CGM observations with either instrument and optimize target selections and observing strategies. Our results show that Lyα emission from the CGM at a redshift of 0.7 will be observable with FIREBall-2 for bright galaxies (NUV∼18 mag), while metal lines like O VI and C IV will remain challenging to detect. HARMONI is found to be well suited to study the CGM at different redshifts with various tracers.</p>


Torus model properties of an ultra-hard X-ray selected sample of Seyfert galaxies

Monthly Notices of the Royal Astronomical Society Oxford University Press 486 (2019) 4917-4935

I Garcia-Benete, C Ramos Almeida, A Alonso-Herrero, M Ward, JA Acosta-Pulido, M Pereira-Santaella, A Hernan-Caballero, A Asensio Ramos, O Gonzalez-Martin, NA Levenson, S Mateos, FJ Carrera, C Ricci, P Roche, I Marquez, C Packham, J Masegosa, L Fuller

We characterize for the first time the torus properties of an ultra-hard X-ray (14–195 keV) volume-limited (DL &lt; 40 Mpc) sample of 24 Seyfert (Sy) galaxies (BCS40 sample). The sample was selected from the Swift/BAT nine-month catalogue. We use high angular resolution nuclear infrared (IR) photometry and N-band spectroscopy, the CLUMPY torus models and a Bayesian tool to characterize the properties of the nuclear dust. In the case of the Sy1s, we estimate the accretion disc contribution to the subarcsecond resolution nuclear IR SEDs (∼0.4 arcsec) which is, on average, 46 ± 28, 23 ± 13, and 11 ± 5 per cent in the J, H, and K bands, respectively. This indicates that the accretion disc templates that assume a steep fall for longer wavelengths than 1 μm might underestimate its contribution to the near-IR emission. Using both optical (broad versus narrow lines) and X-ray (unabsorbed versus absorbed) classifications, we compare the global posterior distribution of the torus model parameters. We confirm that Sy2s have larger values of the torus covering factor (CT ∼ 0.95) than Sy1s (CT ∼ 0.65) in our volume-limited Seyfert sample. These findings are independent of whether we use an optical or X-ray classification. We find that the torus covering factor remains essentially constant within the errors in our luminosity range and there is no clear dependence with the Eddington ratio. Finally, we find tentative evidence that even an ultra-hard X-ray selection is missing a significant fraction of highly absorbed type 2 sources with very high covering factor tori.


High angular resolution ALMA images of dust and molecules in the SN 1987A ejecta

Astrophysical Journal American Astronomical Society 886 (2019) 51

P Cigan, M Matsuura, HL Gomez, R Indebetouw, P Roche

We present high angular resolution (~80 mas) ALMA continuum images of the SN 1987A system, together with CO J = 2 $\to $ 1, J = 6 $\to $ 5, and SiO J = 5 $\to $ 4 to J = 7 $\to $ 6 images, which clearly resolve the ejecta (dust continuum and molecules) and ring (synchrotron continuum) components. Dust in the ejecta is asymmetric and clumpy, and overall the dust fills the spatial void seen in Hα images, filling that region with material from heavier elements. The dust clumps generally fill the space where CO J = 6 $\to $ 5 is fainter, tentatively indicating that these dust clumps and CO are locationally and chemically linked. In these regions, carbonaceous dust grains might have formed after dissociation of CO. The dust grains would have cooled by radiation, and subsequent collisions of grains with gas would also cool the gas, suppressing the CO J = 6 $\to $ 5 intensity. The data show a dust peak spatially coincident with the molecular hole seen in previous ALMA CO J = 2 $\to $ 1 and SiO J = 5 $\to $ 4 images. That dust peak, combined with CO and SiO line spectra, suggests that the dust and gas could be at higher temperatures than the surrounding material, though higher density cannot be totally excluded. One of the possibilities is that a compact source provides additional heat at that location. Fits to the far-infrared–millimeter spectral energy distribution give ejecta dust temperatures of 18–23 K. We revise the ejecta dust mass to M dust = 0.2–0.4 ${M}_{\odot }$ for carbon or silicate grains, or a maximum of <0.7 ${M}_{\odot }$ for a mixture of grain species, using the predicted nucleosynthesis yields as an upper limit.


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

Monthly Notices of the Royal Astronomical Society Oxford University Press 482 (2018) 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 Gómez-Guijarro, M Stockmann, J Huang, C Kramer

We combine new CO(1–0) line observations of 24 intermediate redshift galaxies (0.03 &lt; z &lt; 0.28) along with literature data of galaxies at 0 &lt; z &lt; 4 to explore scaling relations between the dust and gas content using polycyclic aromatic hydrocarbon (PAH) 6.2 μm (L6.2), CO (⁠L′CO⁠), and infrared (LIR) luminosities for a wide range of redshifts and physical environments. Our analysis confirms the existence of a universal L6.2–L′CO correlation followed by normal star-forming galaxies (SFGs) and starbursts (SBs) at all redshifts. This relation is also followed by local ultraluminous infrared galaxies that appear as outliers in the L6.2–LIR and LIR–L′CO relations defined by normal SFGs. The emerging tight (σ ≈ 0.26 dex) and linear (α = 1.03) relation between L6.2 and L′CO indicates a L6.2 to molecular gas (⁠MH2⁠) conversion factor of α6.2 = MH2/L6.2 = (2.7 ± 1.3) × αCO, where αCO is the L′CO to MH2 conversion factor. We also find that on galaxy integrated scales, PAH emission is better correlated with cold rather than with warm dust emission, suggesting that PAHs are associated with the diffuse cold dust, which is another proxy for MH2⁠. Focusing on normal SFGs among our sample, we employ the dust continuum emission to derive MH2 estimates and find a constant MH2/L6.2 ratio of α6.2 = 12.3 M⊙/L⊙(σ ≈ 0.3 dex). This ratio is in excellent agreement with the L′CO-based MH2/L6.2 values for αCO = 4.5 M⊙/(K km s−1 pc2) which is typical of normal SFGs. We propose that the presented L6.2–L′CO and L6.2–MH2 relations will serve as useful tools for the determination of the physical properties of high-z SFGs, for which PAH emission will be routinely detected by the James Webb Space Telescope.


Construction progress of WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope

Proceedings Volume 10702, Ground-based and Airborne Instrumentation for Astronomy VII Society of Photo-optical Instrumentation Engineers 10702 (2018)

G Dalton, S Trager, DC Abrams, I Lewis, M Brock, E Schallig, E al.

We present an update on the overall construction progress of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), now that all the major fabrication contracts are in place. We also present a summary of the current planning behind the 5-year initial phase of survey operations, and some detailed end-to-end science simulations that have been effected to evaluate the final on-sky performance after data processing. WEAVE will provide optical ground-based follow up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single (dual-beam) spectrograph, with total of 16k spectral pixels, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000. The project has experienced some delays in procurement and now has first light expected for the middle of 2019.


First lab results of the WEAVE fibre positioner system

Ground-based and Airborne Instrumentation for Astronomy VII Society of Photo-optical Instrumentation Engineers (2018)

EJJ Schallig, IJ Lewis, G Dalton, M Brock, D Terrett, DC Abrams, K Middleton, G Bishop, JAL Aguerri, P Bonifacio, EC Licea, SC Trager, A Vallenari

WEAVE is the new wide-field spectroscopy facility for the prime focus of the William Herschel Telescope on La Palma in the Canary Islands, Spain. It is a multi-object “pick-and-place” fibre-fed spectrograph with a 960 fibre multiplex behind a new dedicated 2° prime focus corrector. We provide an update on the fibre positioner's technical progress. The hardware has been fully assembled and integrated with its control system for testing. We have made initial calibrations and are starting to move test fibres. In the near future we will dismantle for final modifications and surface anodising, before final reassembly and full fibre installation.


Simulating surveys for ELT-MOSAIC: Status of the MOSAIC science case after phase A

Ground-based and Airborne Instrumentation for Astronomy VII Society of Photo-optical Instrumentation Engineers (2018)

M Puech, CJ Evans, K Disseau, J Japelj, OH Ramirez-Agudelo, H Rahmani, M Trevisan, JL Wang, M Rodrigues, R Sanchez-Janssen, Y Yang, F Hammer, L Kaper, SL Morris, B Barbuy, J-G Cuby, G Dalton, E Fitzsimmons, P Jagourel

We present the consolidated scientific case for multi-object spectroscopy with the MOSAIC concept on the European ELT. The cases span the full range of ELT science and require either ‘high multiplex’ or ‘high definition’ observations to best exploit the excellent sensitivity and wide field-of-view of the telescope. Following scientific prioritisation by the Science Team during the recent Phase A study of the MOSAIC concept, we highlight four key surveys designed for the instrument using detailed simulations of its scientific performance. We discuss future ways to optimise the conceptual design of MOSAIC in Phase B, and illustrate its competitiveness and unique capabilities by comparison with other facilities that will be available in the 2020s.


WAS: The archive for the WEAVE spectrograph

Proceedings of SPIE - The International Society for Optical Engineering 10015 (2018)

J Guerra, A Martin, E Molinari, M Lodi, GB Dalton, SC Trager, DC Abrams, P Bonifacio, JAL Aguerri, A Vallenari, EEC Licea, KF Middleton


Near infrared throughput and stray light measurements of diffraction gratings for ELT-HARMONI

Proceedings of SPIE Society of Photo-optical Instrumentation Engineers 10706 (2018)

M Rodrigues, J Capone, F Clarke, A Earle, T Foster, J Lynn, K Obrien, M Tecza, NA Thatte, I Tosh, A Hidalgo Valadez, IJ Lewis


A Two-dimensional Spectroscopic Study of Emission-line Galaxies in the Faint Infrared Grism Survey (FIGS). I. Detection Method and Catalog

ASTROPHYSICAL JOURNAL 868 (2018) ARTN 61

N Pirzkal, B Rothberg, RE Ryan, S Malhotra, J Rhoads, N Grogin, E Curtis-Lake, J Chevallard, S Charlot, SL Finkelstein, AM Koekemoer, P Ghavamian, M Rodrigues, F Hammer, M Puech, RL Larson, L Christensen, A Cimatti, I Ferreras, JP Gardner, C Gronwall, NP Hathi, B Joshi, H Kuntschner, GR Meurer, RW O'Connell, G Oestlin, A Pasquali, J Pharo, AN Straughn, JR Walsh, D Watson, RA Windhorst, NL Zakamska


Spatially resolved cold molecular outflows in ULIRGs

Astronomy and Astrophysics Springer Nature (2018)

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 3 low-z (~350 Mpc) ULIRG systems (6 nuclei) observed with ALMA at high-spatial resolution (~500 pc). We detect massive cold molecular gas outflows in 5 out of 6 nuclei (0.3-5)x10^8 Msun. These outflows are spatially resolved with deprojected radii of 0.25-1 kpc although high-velocity molecular gas is detected up to ~0.5-1.8 kpc (1-6 kpc deprojected). The mass outflow rates are 12-400 Msun/yr and the inclination corrected average velocity of the outflowing gas 350-550 km/s (v_max = 500-900 km/s). The origin of these outflows can be explained by the nuclear starbursts although the contribution of an obscured AGN can not 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, the outflow PA is clearly not along the kinematic minor axis. The outflow depletion times are 15-80 Myr which are slightly shorter than the star-formation (SF) depletion times (30-80 Myr). However, we estimate that only 15-30% of the outflowing 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 quench the nuclear starbursts. These outflows would be consistent with being driven by radiation pressure (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. 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. (Abridged)


Opto-mechanical designs for the HARMONI adaptive optics systems

Proceedings of SPIE SPIE 10703 (2018)

K Dohlen, TJ Morris, J Piqueras Lopez, A Calcines-Rosario, A Costille, M Dubbeldam, K El Hadi, T Fusco, M Llored, B Neichel, S Pascal, J-F Sauvage, P Vola, F Clarke, H Schnetler, I Bryson, N Thatte

HARMONI is a visible and near-infrared integral field spectrograph equipped with two complementary adaptive optics systems, fully integrated within the instrument. A Single Conjugate AO (SCAO) system offers high performance for a limited sky coverage and a Laser Tomographic AO (LTAO) system provides AO correction with a very high sky-coverage. While the deformable mirror performing real-time correction of the atmospheric disturbances is located within the telescope itself, the instrument contains a suite of state-of-the-art and innovative wavefront sensor systems. Laser guide star sensors (LGSS) are located at the entrance of the instrument and fed by a dichroic beam splitter, while the various natural guide star sensors for LTAO and SCAO are located close to the science focal plane. We present opto-mechanical architecture and design at PDR level for these wavefront sensor systems.


Resolving star formation on subkiloparsec scales in the high-redshift galaxy SDP.11 using gravitational lensing

Astrophysical Journal American Astronomical Society 867 (2018) 140

C Lamarche, A Verma, A Vishwas, GJ Stacey, D Brisbin, C Ferkinhoff, T Nikola, SJU Higdon, J Higdon, M Tecza

We investigate the properties of the interstellar medium, star formation, and the current-day stellar population in the strongly lensed star-forming galaxy H-ATLAS J091043.1-000321 (SDP.11), at z = 1.7830, using new Herschel and Atacama Large Millimeter/submillimeter Array (ALMA) observations of far-infrared fine-structure lines of carbon, oxygen, and nitrogen. We report detections of the [O iii] 52 μm, [N iii] 57 μm, and [O i] 63 μm lines from Herschel/PACS, and present high-resolution imaging of the [C ii] 158 μm line, and underlying continuum, using ALMA. We resolve the [C ii] line emission into two spatially offset Einstein rings, tracing the red and blue velocity components of the line, in the ALMA/Band 9 observations at 0farcs2 resolution. The values seen in the [C ii]/far-infrared (FIR) ratio map, as low as ~0.02% at the peak of the dust continuum, are similar to those of local ULIRGs, suggesting an intense starburst in this source. This is consistent with the high intrinsic FIR luminosity (~3 × 1012 L ⊙), ~16 Myr gas depletion timescale, and lesssim8 Myr timescale since the last starburst episode, estimated from the hardness of the UV radiation field. By applying gravitational lensing models to the visibilities in the uv-plane, we find that the lensing magnification factor varies by a factor of two across SDP.11, affecting the observed line profiles. After correcting for the effects of differential lensing, a symmetric line profile is recovered, suggesting that the starburst present here may not be the result of a major merger, as is the case for local ULIRGs, but instead could be powered by star formation activity spread across a 3–5 kpc rotating disk.


ELT HARMONI: Image Slicer Preliminary Design

GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VII 10702 (2018) UNSP 1070296

F Laurent, D Boudon, J Kosmalski, M Loupias, G Raffault, A Remillieux, N Thatte, I Bryson, H Schnetler, F Clarke, M Tecza

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