Euclid preparation: XVIII. The NISP photometric system

Galaxie

Balancing the energy budget between star formation and active galactic nuclei in high-redshift infrared luminous galaxies

We present deep Spitzer mid-infrared spectroscopy, along with 16, 24, 70, and 850 μm photometry, for 22 galaxies located in the Great Observatories Origins Deep Survey-North (GOODS-N) field. The sample spans a redshift range of 0.6 lsim z lsim 2.6, 24 μm flux densities between ~0.2 and 1.2 mJy, and consists of submillimeter galaxies (SMGs), X-ray or optically selected active galactic nuclei (AGNs), and optically faint (zAB > 25 mag) sources. We find that infrared (IR; 8-1000 μm) luminosities derived by fitting local spectral energy distributions (SEDs) with 24 μm photometry alone are well matched to those when additional mid-infrared spectroscopic and longer wavelength photometric data are used for galaxies having z lsim 1.4 and 24 μm-derived IR luminosities typically lsim3 × 1012 L sun. However, for galaxies in the redshift range between 1.4 lsim z lsim 2.6, typically having 24-μm-derived IR luminosities gsim3 × 1012 L sun, IR luminosities are overestimated by an average factor of ~5 when SED fitting with 24 μm photometry alone. This result arises partly due to the fact that high-redshift galaxies exhibit aromatic feature equivalent widths that are large compared to local galaxies of similar luminosities. Using improved estimates for the IR luminosities of these sources, we investigate whether their infrared emission is found to be in excess relative to that expected based on extinction-corrected UV star formation rates (SFRs), possibly suggesting the presence of an obscured AGN. Through a spectral decomposition of mid-infrared spectroscopic data, we are able to isolate the fraction of IR luminosity arising from an AGN as opposed to star formation activity. This fraction is only able to account for ~30% of the total IR luminosity among the entire sample and ~35% of the "excess" IR emission among these sources, on average, suggesting that AGNs are not the dominant cause of the inferred "mid-infrared excesses" in these systems. Of the sources identified as having mid-infrared excesses, half are accounted for by using proper bolometric corrections while half show the presence of obscured AGNs. This implies sky and space densities for Compton-thick AGNs of ~1600 deg-2 and ~1.3 × 10-4 Mpc-3, respectively. We also note that IR luminosities derived from SED fitting the mid-infrared and 70 μm broadband photometry agree within ~50% to those values estimated using the additional mid-infrared spectroscopic and submillimeter data. An inspection of the far-infrared (FIR)-radio correlation shows no evidence for evolution over this redshift range. However, we find that the SMGs have IR/radio ratios which are a factor of ~3 lower, on average, than what is measured for star-forming galaxies in the local universe

Detection of Far-Infrared and Polycyclic Aromatic Hydrocarbon Emission from the Cosmic Eye: Probing the Dust and Star Formation of Lyman Break Galaxies

We report the results of a Spitzer infrared (IR) study of the Cosmic Eye, a strongly lensed, L*UV Lyman break galaxy (LBG) at z = 3.074. We obtained Spitzer mid-IR spectroscopy as well as MIPS 24 and 70 μm photometry. The Eye is detected with high significance at both 24 and 70 μm and, when including a flux limit at 3.5 mm, we estimate an IR luminosity of L IR = 8.3+4.7 –4.4 × 1011 L ☉ assuming a magnification of 28± 3. This L IR is eight times lower than that predicted from the rest-frame ultraviolet properties assuming a Calzetti reddening law. This has also been observed in other young LBGs, and indicates that the dust reddening law may be steeper in these galaxies. The mid-IR spectrum shows strong polycyclic aromatic hydrocarbon (PAH) emission at 6.2 and 7.7 μm, with equivalent widths near the maximum values observed in star-forming galaxies at any redshift. The L PAH-to-L IR ratio lies close to the relation measured in local starbursts. Therefore, L PAH or L MIR may be used to estimate L IR, and thus star formation rate, of LBGs, whose fluxes at longer wavelengths are typically below current confusion limits. We also report the highest redshift detection of the 3.3 μm PAH emission feature. The PAH ratio, L 6.2/L 3.3 = 5.1 ± 2.7, and the PAH-to-LIR ratio, L 3.3/L IR = 8.5 ± 4.7 × 10–4, are both in agreement with measurements in local starbursts and ultraluminous infrared galaxies (ULIRGs), suggesting that this line may serve as a good proxy for L PAH or L IR at z > 3 with the James Webb Space Telescope

The Mass-Metallicity Relation at Cosmic Noon in Overdense Environments: First Results from the MAMMOTH-Grism HST Slitless Spectroscopic Survey

The MAMMOTH-Grism slitless spectroscopic survey is a Hubble Space Telescope (HST) cycle 28 medium program, which is obtaining 45 orbits of WFC3/IR grism spectroscopy in the density peak regions of three massive galaxy protoclusters at z = 2-3 discovered using the MAMMOTH technique. We introduce this survey by presenting the first measurement of the mass-metallicity relation (MZR) at high redshift in overdense environments via grism spectroscopy. From the completed MAMMOTH-Grism observations in the field of the BOSS1244 protocluster at z = 2.24 ± 0.02, we secure a sample of 36 protocluster member galaxies at z ≈ 2.24, showing strong nebular emission lines ([O III], Hβ, and [O II]) in their G141 spectra. Using the multi-wavelength broadband deep imaging from HST and ground-based telescopes, we measure their stellar masses in the range of [109, 1010.4] M ⊙, instantaneous star formation rates (SFR) from 10 to 240 M ⊙ yr-1, and global gas-phase metallicities [13,1] of solar. Compared with similarly selected field-galaxy samples at the same redshift, our galaxies show, on average, increased SFRs by ∼0.06 dex and ∼0.18 dex at ∼1010.1 M ⊙ and ∼109.8 M ⊙, respectively. Using the stacked spectra of our sample galaxies, we derive the MZR in the BOSS1244 protocluster core as 12+log(O/H)=0.136±0.018 × log(M∗/M⊙)+7.082±0.175, showing a significantly shallower slope than that in the field. This shallow MZR slope is likely caused by the combined effects of efficient recycling of feedback-driven winds and cold-mode gas accretion in protocluster environments. The former effect helps low-mass galaxies residing in overdensities retain their metal production, whereas the latter effect dilutes the metal content of high-mass galaxies, making them more metal-poor than their coeval field counterparts. © 2022. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

LOCAL STARBURSTS: PERSPECTIVES FROM THE OPTICAL

Keywords: The optical regime is historically the best-studied wavelength range. Gas ionized by massive stars produces optical emission lines that have been used to derive indicators of star–formation rate, metallicity, dust reddening, and the ionization conditions of the interstellar medium. Absorptions lines have been used to measure velocity dispersions, and the 4000 A break has been shown to be a useful indicator of the mean age of stellar populations. I briefly summarize some recent work done on, specifically, star formation rate indicators, in view of their importance for understanding star–forming galaxies at high redshift. 1

The High Latitude Spectroscopic Survey on the Nancy Grace Roman Space Telescope

The Nancy Grace Roman Space Telescope will conduct a High Latitude Spectroscopic Survey (HLSS) over a large volume at high redshift, using the near-IR grism (1.0-1.93 μm, R = 435-865) and the 0.28 deg2 wide-field camera. We present a reference HLSS that maps 2000 deg2 and achieves an emission-line flux limit of 10-16 erg s-1 cm-2 at 6.5σ, requiring ∼0.6 yr of observing time. We summarize the flowdown of the Roman science objectives to the science and technical requirements of the HLSS. We construct a mock redshift survey over the full HLSS volume by applying a semianalytic galaxy formation model to a cosmological N-body simulation and use this mock survey to create pixel-level simulations of 4 deg2 of HLSS grism spectroscopy. We find that the reference HLSS would measure ∼10 million Hα galaxy redshifts that densely map large-scale structure at z = 1-2 and 2 million [O iii] galaxy redshifts that sparsely map structures at z = 2-3. We forecast the performance of this survey for measurements of the cosmic expansion history with baryon acoustic oscillations and the growth of large-scale structure with redshift-space distortions. We also study possible deviations from the reference design and find that a deep HLSS at f line > 7 × 10-17 erg s-1 cm-2 over 4000 deg2 (requiring ∼1.5 yr of observing time) provides the most compelling stand-alone constraints on dark energy from Roman alone. This provides a useful reference for future optimizations. The reference survey, simulated data sets, and forecasts presented here will inform community decisions on the final scope and design of the Roman HLSS. © 2022. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The CatWISE2020 Catalog

The CatWISE2020 Catalog consists of 1,890,715,640 sources over the entire sky selected from Wide-field Infrared Survey Explorer (WISE) and NEOWISE survey data at 3.4 and 4.6 μm (W1 and W2) collected from 2010 January 7 to 2018 December 13. This data set adds two years to that used for the CatWISE Preliminary Catalog, bringing the total to six times as many exposures spanning over 16 times as large a time baseline as the AllWISE catalog. The other major change from the CatWISE Preliminary Catalog is that the detection list for the CatWISE2020 Catalog was generated using crowdsource from Schlafly et al., while the CatWISE Preliminary Catalog used the detection software used for AllWISE. These two factors result in roughly twice as many sources in the CatWISE2020 Catalog. The scatter with respect to Spitzer photometry at faint magnitudes in the COSMOS field, which is out of the Galactic Plane and at low ecliptic latitude (corresponding to lower WISE coverage depth) is similar to that for the CatWISE Preliminary Catalog. The 90% completeness depth for the CatWISE2020 Catalog is at W1 = 17.7 mag and W2 = 17.5 mag, 1.7 mag deeper than in the CatWISE Preliminary Catalog. In comparison to Gaia, CatWISE2020 motions are accurate at the 20 mas yr-1 level for W1∼15 mag sources and at the ∼100 mas yr-1 level for W1∼17 mag sources. This level of accuracy represents a 12 improvement over AllWISE. The CatWISE catalogs are available in the WISE/NEOWISE Enhanced and Contributed Products area of the NASA/IPAC Infrared Science Archive. © 2021. The American Astronomical Society. All rights reserved..Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]