- ID:
- ivo://CDS.VizieR/J/ApJS/239/27
- Title:
- LEGA-C DR2: galaxies in the COSMOS field
- Short Name:
- J/ApJS/239/27
- Date:
- 01 Mar 2022
- Publisher:
- CDS
- Description:
- We present the second data release of the Large Early Galaxy Astrophysics Census (LEGA-C), an ESO 130-night public spectroscopic survey conducted with VIMOS on the Very Large Telescope. We release 1988 spectra with typical continuum S/N~20{AA}^-1^ of galaxies at 0.6<~z<~1.0, each observed for ~20hr and fully reduced with a custom-built pipeline. We also release a catalog with spectroscopic redshifts, emission-line fluxes, Lick/IDS indices, and observed stellar and gas velocity dispersions that are spatially integrated quantities, including both rotational motions and genuine dispersion. To illustrate the new parameter space in the intermediate-redshift regime probed by LEGA-C, we explore relationships between dynamical and stellar population properties. The star-forming galaxies typically have observed stellar velocity dispersions of ~150km/s and strong H{delta} absorption (H{delta}_A_~5{AA}), while passive galaxies have higher observed stellar velocity dispersions (~200km/s) and weak H{delta} absorption (H{delta}_A_~0{AA}). Strong [OIII]5007/H{beta} ratios tend to occur mostly for galaxies with weak H{delta}_A_ or galaxies with higher observed velocity dispersion. Beyond these broad trends, we find a diversity of possible combinations of rest-frame colors, absorption-line strengths, and emission-line detections, illustrating the utility of spectroscopic measurements to more accurately understand galaxy evolution.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/837/120
- Title:
- Lick Observatory Supernova Search (LOSS) revisited
- Short Name:
- J/ApJ/837/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most types of supernovae (SNe) have yet to be connected with their progenitor stellar systems. Here, we reanalyze the 10-year SN sample collected during 1998-2008 by the Lick Observatory Supernova Search (LOSS; see Leaman+, 2011, J/MNRAS/412/1419) in order to constrain the progenitors of SNe Ia and stripped-envelope SNe (SE SNe, i.e., SNe IIb, Ib, Ic, and broad-lined Ic). We matched the LOSS galaxy sample with spectroscopy from the Sloan Digital Sky Survey (SDSS) and measured SN rates as a function of galaxy stellar mass, specific star formation rate, and oxygen abundance (metallicity). We find significant correlations between the SN rates and all three galaxy properties. The SN Ia correlations are consistent with other measurements, as well as with our previous explanation of these measurements in the form of a combination of the SN Ia delay-time distribution and the correlation between galaxy mass and age. The ratio between the SE SN and SN II rates declines significantly in low-mass galaxies. This rules out single stars as SE SN progenitors, and is consistent with predictions from binary-system progenitor models. Using well-known galaxy scaling relations, any correlation between the rates and one of the galaxy properties examined here can be expressed as a correlation with the other two. These redundant correlations preclude us from establishing causality-that is, from ascertaining which of the galaxy properties (or their combination) is the physical driver for the difference between the SE SN and SN II rates. We outline several methods that have the potential to overcome this problem in future works.
- ID:
- ivo://CDS.VizieR/J/ApJ/795/165
- Title:
- Line ratios in z~2-3 galaxies from KBSS-MOSFIRE
- Short Name:
- J/ApJ/795/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present initial results of a deep near-IR spectroscopic survey covering the 15 fields of the Keck Baryonic Structure Survey using the recently commissioned MOSFIRE spectrometer on the Keck 1 telescope. We focus on a sample of 251 galaxies with redshifts 2.0<z<2.6, star formation rates (SFRs) 2<~SFR<~200 M_{sun}_/yr, and stellar masses 8.6<log(M_*_/M_{sun}_)<11.4, with high-quality spectra in both H- and K-band atmospheric windows. We show unambiguously that the locus of z~2.3 galaxies in the "BPT" nebular diagnostic diagram exhibits an almost entirely disjointed, yet similarly tight, relationship between the line ratios [N II] {lambda}6585/H{alpha} and [O III]/H{beta} as compared to local galaxies. Using photoionization models, we argue that the offset of the z~2.3 BPT locus relative to that at z~0 is caused by a combination of harder stellar ionizing radiation field, higher ionization parameter, and higher N/O at a given O/H compared to most local galaxies, and that the position of a galaxy along the z~2.3 star-forming BPT locus is surprisingly insensitive to gas-phase oxygen abundance. The observed nebular emission line ratios are most easily reproduced by models in which the net stellar ionizing radiation field resembles a blackbody with effective temperature T_eff_=50000-60000 K, the gas-phase oxygen abundances lie in the range 0.2<Z/Z_{sun}_<1.0, and the ratio of gas-phase N/O is close to the solar value. We critically assess the applicability at high redshift of commonly used strong line indices for estimating gas-phase metallicity, and consider the implications of the small intrinsic scatter of the empirical relationship between excitation-sensitive line indices and M_*_(i.e., the "mass-metallicity" relation) at z=~2.3.
- ID:
- ivo://CDS.VizieR/J/ApJ/859/53
- Title:
- Ly{alpha} candidates from a MUSE survey of 6 AGNs
- Short Name:
- J/ApJ/859/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent theoretical models suggest that the early phase of galaxy formation could involve an epoch when galaxies are gas rich but inefficient at forming stars: a "dark galaxy" phase. Here, we report the results of our Multi-Unit Spectroscopic Explorer (MUSE) survey for dark galaxies fluorescently illuminated by quasars at z>3. Compared to previous studies which are based on deep narrowband (NB) imaging, our integral field survey provides a nearly uniform sensitivity coverage over a large volume in redshift space around the quasars as well as full spectral information at each location. Thanks to these unique features, we are able to build control samples at large redshift distances from the quasars using the same data taken under the same conditions. By comparing the rest-frame equivalent width (EW0) distributions of the Ly{alpha} sources detected in proximity to the quasars and in control samples, we detect a clear correlation between the locations of high-EW0 objects and the quasars. This correlation is not seen in other properties, such as Ly{alpha} luminosities or volume overdensities, suggesting the possible fluorescent nature of at least some of these objects. Among these, we find six sources without continuum counterparts and EW0 limits larger than 240{AA} that are the best candidates for dark galaxies in our survey at z>3.5. The volume densities and properties, including inferred gas masses and star formation efficiencies, of these dark galaxy candidates are similar to those of previously detected candidates at z~2.4 in NB surveys. Moreover, if the most distant of these are fluorescently illuminated by the quasar, our results also provide a lower limit of t=60Myr on the quasar lifetime.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/5
- Title:
- MACT survey. I. Opt. spectroscopy in Subaru Deep Field
- Short Name:
- J/ApJS/226/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep rest-frame optical spectroscopy is critical for characterizing and understanding the physical conditions and properties of the ionized gas in galaxies. Here, we present a new spectroscopic survey called "Metal Abundances across Cosmic Time" or MACT, which will obtain rest-frame optical spectra for ~3000 emission-line galaxies. This paper describes the optical spectroscopy that has been conducted with MMT/Hectospec and Keck/DEIMOS for ~1900 z=0.1-1 emission-line galaxies selected from our narrowband and intermediate-band imaging in the Subaru Deep Field. In addition, we present a sample of 164 galaxies for which we have measured the weak [OIII]{lambda}4363 line (66 with at least 3{sigma} detections and 98 with significant upper limits). This nebular emission line determines the gas-phase metallicity by measuring the electron temperature of the ionized gas. This paper presents the optical spectra, emission-line measurements, interstellar properties (e.g., metallicity, gas density), and stellar properties (e.g., star formation rates, stellar mass). Paper II of the MACT survey (Ly et al. 2016ApJ...828...67L) presents the first results on the stellar mass-gas metallicity relation at z<=1 using the sample with [OIII]{lambda}4363 measurements.
- ID:
- ivo://CDS.VizieR/J/ApJS/240/33
- Title:
- MaDCoWS. I. Catalog of z~1 galaxy clusters
- Short Name:
- J/ApJS/240/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Massive and Distant Clusters of WISE Survey (MaDCoWS), a search for galaxy clusters at 0.7<=z<=1.5 based upon data from the Wide-field Infrared Survey Explorer (WISE) mission. MaDCoWS is the first cluster survey capable of discovering massive clusters at these redshifts over the full extragalactic sky. The search is divided into two regions-the region of the extragalactic sky covered by Pan-STARRS ({delta}{>}-30{deg}) and the remainder of the southern extragalactic sky at {delta}{<}-30{deg} for which shallower optical data from the SuperCOSMOS Sky Survey is available. In this paper, we describe the search algorithm, characterize the sample, and present the first MaDCoWS data release-catalogs of the 2433 highest amplitude detections in the WISE-Pan-STARRS region and the 250 highest amplitude detections in the WISE-SuperCOSMOS region. A total of 1723 of the detections from the WISE-Pan-STARRS sample have also been observed with the Spitzer Space Telescope, providing photometric redshifts and richnesses, and an additional 64 detections within the WISE-SuperCOSMOS region also have photometric redshifts and richnesses. Spectroscopic redshifts for 38 MaDCoWS clusters with IRAC photometry demonstrate that the photometric redshifts have an uncertainty of {sigma}z/(1+z)~0.036. Combining the richness measurements with Sunyaev-Zel'dovich observations of MaDCoWS clusters, we also present a preliminary mass-richness relation that can be used to infer the approximate mass distribution of the full sample. The estimated median mass for the WISE-Pan-STARRS catalog is M_500_=1.6_-0.8_^+0.7^x10^14^M_{sun}_, with the Sunyaev-Zel'dovich data confirming that we detect clusters with masses up to M_500_~5x10^14^M_{sun}_ (_M200_~10^15^M_{sun}_).
- ID:
- ivo://CDS.VizieR/J/ApJ/883/11
- Title:
- Magellan/IMACS spectra of Crater II & Hercules
- Short Name:
- J/ApJ/883/11
- Date:
- 21 Jan 2022 09:25:05
- Publisher:
- CDS
- Description:
- We investigate the possibility that the dwarf galaxies Crater II and Hercules have previously been tidally stripped by the Milky Way. We present Magellan/IMACS spectra of candidate member stars in both objects. We identify 37 members of Crater II, 25 of which have velocity measurements in the literature, and we classify three stars within that subset as possible binaries. We find that including or removing these binary candidates does not change the derived velocity dispersion of Crater II. Excluding the binary candidates, we measure a velocity dispersion of {sigma}_Vlos_=2.7_-0.4_^+0.5^km/s, corresponding to M/L=47_-13_^+17^M_{sun}_/L_{sun}_. We measure a mean metallicity of [Fe/H]=-1.95_-0.05_^+0.06^, with a dispersion of {sigma}_[Fe/H]_=0.18_-0.08_^+0.06^. Our velocity dispersion and metallicity measurements agree with previous measurements for Crater II, and confirm that the galaxy resides in a kinematically cold dark-matter halo. We also search for spectroscopic members stripped from Hercules in the possible extratidal stellar overdensities surrounding the dwarf. For both galaxies, we calculate proper motions using Gaia DR2 astrometry, and use their full 6D phase space information to evaluate the probability that their orbits approach sufficiently close to the Milky Way to experience tidal stripping. Given the available kinematic data, we find a probability of ~40% that Hercules has suffered tidal stripping. The proper motion of Crater II makes it almost certain to be stripped.
118. MALT90 Catalogue
- ID:
- ivo://CDS.VizieR/J/other/PASA/33.30
- Title:
- MALT90 Catalogue
- Short Name:
- J/other/PASA/33.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Millimetre Astronomy Legacy Team 90GHz survey aims to characterise the physical and chemical evolution of high-mass clumps. Recently completed, it mapped 90GHz line emission towards 3246 high-mass clumps identified from the ATLASGAL 870um Galactic plane survey. By utilising the broad frequency coverage of the Mopra telescope's spectrometer, maps in 16 different emission lines were simultaneously obtained. Here, we describe the first catalogue of the detected line emission, generated by Gaussian profile fitting to spectra extracted towards each clumps' 870um dust continuum peak. Synthetic spectra show that the catalogue has a completeness of >95%, a probability of a false-positive detection of <0.3%, and a relative uncertainty in the measured quantities of <20% over the range of detection criteria. The detection rates are highest for the (1-0) transitions of HCO^+^, HNC, N_2_H^+^, and HCN (~77-89%). Almost all clumps (~95%) are detected in at least one of the molecular transitions, just over half of the clumps (~53%) are detected in four or more of the transitions, while only one clump is detected in 13 transitions. We find several striking trends in the ensemble of properties for the different molecular transitions when plotted as a function of the clumps' evolutionary state as estimated from Spitzer mid-IR images, including (1) HNC is relatively brighter in colder, less evolved clumps than those that show active star formation, (2) N2H+ is relatively brighter in the earlier stages, (3) that the observed optical depth decreases as the clumps evolve, and (4) the optically thickest HCO^+^ emission shows a 'blue-red asymmetry' indicating overall collapse that monotonically decreases as the clumps evolve. This catalogue represents the largest compiled database of line emission towards high-mass clumps and is a valuable data set for detailed studies of these objects.
- ID:
- ivo://CDS.VizieR/V/127A
- Title:
- MASH Catalogues of Planetary Nebulae
- Short Name:
- V/127A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Macquarie/AAO/Strasbourg H{alpha} Planetary Nebula Catalogue (MASH) contains 903 new true, likely and possible Galactic Planetary Nebulae (PNe) discovered from the AAO/UKST H{alpha} survey of the southern Galactic plane. The combination of depth, resolution, uniformity, and areal coverage of the H {alpha}survey has opened up an hitherto unexplored region of parameter space permitting the detection of this significant new PN sample. This catalogue includes also the spectra of the PNe as FITS files (in the "sp" subdirectory), and a gallery of images created as a combination of the H{alpha} and short red images of the survey. The second part, MASH-II (table mash2.dat) consists of over 300 true, likely and possible new Galactic PNe found after re-examination of the entire AAO/UKST H{alpha} survey of the Southern Galactic Plane in digital form. Over 240 of these new candidates were confirmed as bona fide PNe on the basis of spectroscopic observations. The spectra of this supplement will be available in the future.
- ID:
- ivo://CDS.VizieR/J/ApJ/699/800
- Title:
- Mass functions of active black holes
- Short Name:
- J/ApJ/699/800
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present mass functions of distant actively accreting supermassive black holes residing in luminous quasars discovered in the Large Bright Quasar Survey (LBQS), the Bright Quasar Survey (BQS), and the Fall Equatorial Stripe of the Sloan Digital Sky Survey (SDSS). The quasars cover a wide range of redshifts from the local universe to z=5 and were subject to different selection criteria and flux density limits. This makes these samples complementary and can help us gain additional insight on the true underlying black hole mass distribution free from selection effects and mass estimation errors through future studies. We present the relationships used to estimate the black hole mass based on the MgII emission line; the relations are calibrated to the H{beta} and CIV relations by means of several thousand high-quality SDSS spectra. Mass estimates of the individual black holes of these samples are also presented.