- ID:
- ivo://CDS.VizieR/J/AJ/132/2596
- Title:
- Spectroscopy of Ultraluminous IR galaxies
- Short Name:
- J/AJ/132/2596
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the types of nuclear environments that produce OH megamasers (OHMs) with a study of the optical spectra of 40 OHM host galaxies and a control sample of 30 non-masing (ultra)luminous infrared galaxies ([U]LIRGs). The optical spectrophotometry provides spatially resolved spectra of multiple nuclei in a few of these merging systems. Of the 40 OHMs classified, 33% are starbursts, 42% are LINERs, and 25% are Seyfert 2 galaxies; the classification of the non-masing control sample is similar.
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- ID:
- ivo://CDS.VizieR/J/ApJ/668/853
- Title:
- Spectroscopy of UltraStrong Emission Line galaxies
- Short Name:
- J/ApJ/668/853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the results of a narrowband search for ultrastrong emission line galaxies (USELs) with EW(H{beta})>=30{AA}. A total of 542 candidate galaxies are found in a one-half square degree survey using two ~120{AA} filters centered at 8150 and 9140{AA} with Subaru SuprimeCam. Follow-up spectroscopy for randomly selected objects in the candidate sample with Keck II DEIMOS shows that they consist of [OIII] {lambda}5007-, [OII] {lambda}3727-, and H{alpha}-selected strong emission line galaxies at intermediate redshift (z<1) and Ly{alpha}-emitting galaxies at high redshift (z>>5).
- ID:
- ivo://CDS.VizieR/J/ApJ/708/560
- Title:
- Spectroscopy of UMa II and Coma Ber
- Short Name:
- J/ApJ/708/560
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectra of six metal-poor stars in two of the ultra-faint dwarf galaxies orbiting the Milky Way (MW), Ursa Major II, and Coma Berenices obtained with the Keck/High Resolution Echelle Spectrometer (HIRES). These observations include the first high-resolution spectroscopic observations of extremely metal-poor ([Fe/H]<-3.0) stars not belonging to the MW halo field star population. We obtain abundance measurements and upper limits for 26 elements between carbon and europium. The entire sample of stars spans a range of -3.2<[Fe/H]<-2.3, and we confirm that each galaxy contains a large intrinsic spread of Fe abundances. A comparison with MW halo stars of similar metallicities reveals substantial agreement between the abundance patterns of the ultra-faint dwarf galaxies and the MW halo for the light, {alpha}, and iron-peak elements (C to Zn). The abundances of neutron-capture elements (Sr to Eu) in the ultra-faint dwarf galaxies are extremely low, consistent with the most metal-poor halo stars, but not with the typical halo abundance pattern at [Fe/H]>~-3.0. Not only are our results broadly consistent with a galaxy formation model that predicts that massive dwarf galaxies are the source of the metal-rich component ([Fe/H]>-2.5) of the MW halo, but they also suggest that the faintest known dwarfs may be the primary contributors to the metal-poor end of the MW halo metallicity distribution.
- ID:
- ivo://CDS.VizieR/J/ApJ/693/1713
- Title:
- Spectroscopy of X-ray sources in ECDF-S
- Short Name:
- J/ApJ/693/1713
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of our optical spectroscopy program aimed to provide redshifts and identifications for the X-ray sources in the Extended Chandra Deep Field South. A total of 339 sources were targeted using the IMACS spectrograph at the Magellan telescopes and the VIMOS spectrograph at the VLT. We measured redshifts for 186 X-ray sources, including archival data and a literature search. We find that the active galactic nucleus (AGN) host galaxies have on average redder rest-frame optical colors than nonactive galaxies, and that they live mostly in the "green valley". The dependence of the fraction of AGNs that are obscured on both luminosity and redshift is confirmed at high significance and the observed AGN spatial density is compared with the expectations from existing luminosity functions. These AGNs show a significant difference in the mid-IR to X-ray flux ratio for obscured and unobscured AGNs, which can be explained by the effects of dust self-absorption on the former. This difference is larger for lower luminosity sources, which is consistent with the dust opening angle depending on AGN luminosity.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A85
- Title:
- Spectroscopy of 3<z<4 quiescent galaxies
- Short Name:
- J/A+A/618/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Keck-MOSFIRE H and K spectra for a sample of 24 candidate quiescent galaxies at 3<z<4, identified from their rest-frame UVJ colors and photometric redshifts in the ZFOURGE and 3DHST surveys. With median integration times of one hour in H and five in K, we obtain spectroscopic redshifts for half of the sample, using either Balmer absorption lines or nebular emission lines. We confirm the high accuracy of the photometric redshifts for this spectroscopically-confirmed sample, with a median |Zphot-Zspec|/(1+Zspec) of 1.2%. Two galaxies turn out to be dusty H{alpha} emitters at lower redshifts (z<2.5), and these are the only two detected in the sub-mm with ALMA. High equivalent-width [OIII] emission is observed in two galaxies, contributing up to 30% of the K-band flux and mimicking the UVJ colors of an old stellar population. This implies a failure rate of only 20% for the UVJ selection at these redshifts. Lastly, Balmer absorption features are identified in four galaxies, among the brightest of the sample, confirming the absence of OB stars. We then modeled the spectra and photometry of all quiescent galaxies with a wide range of star-formation histories. We find specific star-formation rates (sSFR) lower than 0.15Gyr^-1^ (a factor of ten below the main sequence) for all but one galaxy, and lower than 0.01Gyr^-1^ for half of the sample. These values are consistent with the observed H{beta} and [OII] luminosities, and the ALMA non-detections. The implied formation histories reveal that these galaxies have quenched on average 300Myr prior to being observed, between z=3.5 and 5, and that half of their stars were formed by z~5.5 with a mean SFR~300M_{sun}_/yr. We finally compared the UVJ selection to a selection based instead on the sSFR, as measured from the photometry. We find that galaxies a factor of ten below the main sequence are 40% more numerous than UVJ-selected quiescent galaxies, implying that the UVJ selection is pure but incomplete. Current models fail at reproducing our observations, and underestimate either the number density of quiescent galaxies by more than an order of magnitude, or the duration of their quiescence by a factor two. Overall, these results confirm the existence of an unexpected population of quiescent galaxies at z>3, and offer the first insights on their formation histories.
- ID:
- ivo://CDS.VizieR/J/ApJ/633/174
- Title:
- Spheroidals and bulge dominated galaxies
- Short Name:
- J/ApJ/633/174
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive catalog of high signal-to-noise ratio spectra obtained with DEIMOS on the Keck II telescope for a sample of F850LP<22.43mag(AB) field spheroidal (E+S0 galaxies; 165) and bulge-dominated disk (61) galaxies in the redshift range 0.2<z<1.2, selected on the basis of visual morphology from the northern field of the Great Observatories Origins Deep Survey (GOODS-N). We discuss sample selection, photometric properties, and spectral reduction. We derive scale lengths, surface brightnesses, and photometric inhomogeneities from the ACS data and redshifts, stellar velocity dispersions, and [OII] and H{delta} equivalent widths from the Keck spectroscopy. Using the published 2Ms Chandra Deep Field-North X-ray catalog (Cat. <J/AJ/126/632>), we identify active galactic nuclei (AGNs) to clarify the origin of emission lines seen in the Keck spectra.
- ID:
- ivo://CDS.VizieR/J/AJ/123/2223
- Title:
- SPICES II: CHANDRA observations of Lynx
- Short Name:
- J/AJ/123/2223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present our first results on field X-ray sources detected in a deep, 184.7ks observation with the Advanced CCD Imaging Spectrometer (ACIS-I) on the Chandra X-Ray Observatory. The observations target the Lynx field (RA=08h48min, DE=+44{deg}54') of SPICES, the Spectroscopic Photometric Infrared-Chosen Extragalactic Survey, which contains three known X-ray-emitting clusters at redshifts of z=0.57, 1.26, and 1.27. Not including the known clusters, in the 17'x17' ACIS-I field we detect 132 sources in the 0.5-2keV (soft) X-ray band down to a limiting flux of ~1.7x10^-16^ergs/cm^2^/s and 11 sources in the 2-10keV (hard) X-ray band down to a limiting flux of ~1.3x10^-15^ergs/cm^2^/s. The combined catalog contains a total of 153 sources, of which 42 are detected only in the soft band and 21 are detected only in the hard band. Confirming previous Chandra results, we find that the fainter sources have harder X-ray spectra, providing a consistent solution to the long-standing "spectral paradox." From deep optical and near-infrared follow-up data, 77% of the X-ray sources have optical counterparts to I=24, and 71% of the X-ray sources have near-infrared counterparts to Ks=20. Four of the 24 sources in the near-IR field are associated with extremely red objects (EROs; I-Ks>=4). We have obtained spectroscopic redshifts with the Keck telescopes of 18 of the Lynx Chandra sources. These sources comprise a mix of broad-lined active galaxies, apparently normal galaxies, and two late-type Galactic dwarfs. Intriguingly, one Galactic source is identified with an M7 dwarf exhibiting nontransient, hard X-ray emission. Thirteen of the Chandra sources are located within regions for which we have Hubble Space Telescope imaging. Nine of the sources are detected, showing a range of morphologies: several show compact cores embedded within diffuse emission, while others are spatially extended showing typical galaxy morphologies. Two of the Chandra sources in this subsample appear to be associated with mergers. We briefly review non-active galactic nucleus mechanisms to produce X-ray emission and discuss properties of the Lynx Chandra sample in relation to other samples of X-ray and non-X-ray sources.
- ID:
- ivo://CDS.VizieR/J/A+A/658/L2
- Title:
- Spiderweb galaxy [CII] 158um spectrum
- Short Name:
- J/A+A/658/L2
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the detection of [CII] 158um emission from the Spiderweb galaxy at z=2.1612 using the Atacama Pathfinder EXperiment. The line profile splits into an active galactic nucleus (AGN) and circum galactic medium (CGM) component previously identified in CO and [CI]. We find that these individual [CII] components are consistent in terms of CO and far-IR luminosity ratios with the populations of other z>~1 AGN and dusty star-forming galaxies. The CGM component dominates the [CII] emission in the 10" APEX beam. Although we do not have spatially resolved data, the close correspondence of the velocity profile with the CO(1-0) detected only on scales of tens of kiloparsecs in CO(1-0) suggests that the [CII] emission is similarly extended, reminiscent of [CII] halos recently found around z>5 galaxies. Comparing the first four ionization states of carbon, we find that the atomic [CI] emission is dominant, which increases its reliability as a molecular mass tracer. Our [CII] detection at 601.8 GHz also demonstrates the feasibility to extend the frequency range of ALMA Band 9 beyond the original specifications.
- ID:
- ivo://CDS.VizieR/J/A+A/570/A55
- Title:
- Spiderweb galaxy 870um and 1.4GHz images
- Short Name:
- J/A+A/570/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present APEX LABOCA 870{mu}m observations of the field around the high-redshift radio galaxy MRC1138-262 at z=2.16. We detect 16 submillimeter galaxies (SMGs) in this ~140-arcmin^2^ bolometer map with flux densities in the range 3-11mJy. The raw number counts indicate a density of SMGs that is up to four times that of blank field surveys. Based on an exquisite multiwavelength database, including VLA 1.4 GHz radio and infrared observations, we investigate whether these sources are members of the protocluster structure at z=~2.2. Using Herschel PACS and SPIRE and Spitzer MIPS photometry, we derive reliable far-infrared (FIR) photometric redshifts for all sources. Follow-up VLT ISAAC and SINFONI NIR spectra confirm that four of these SMGs have redshifts of z=~2.2. We also present evidence that another SMG in this field, detected earlier at 850{mu}m, has a counterpart that exhibits H{alpha} and CO(1-0) emission at z=2.15. Including the radio galaxy and two SMGs with FIR photometric redshifts at z=2.2, we conclude that at least eight submm sources are part of the protocluster at z=2.16 associated with the radio galaxy MRC1138-262. We measure a star formation rate density SFRD~1500M_{sun}_/yr/Mpc^3^, four magnitudes higher than the global SFRD of blank fields at this redshift. Strikingly, these eight sources are concentrated within a region of 2Mpc (the typical size of clusters in the local universe) and are distributed within the filaments traced by the HAEs at z=~2.2. This concentration of massive, dusty starbursts is not centered on the submillimeter-bright radio galaxy which could support the infalling of these sources into the cluster center. Approximately half (6/11) of the SMGs that are covered by the H{alpha} imaging data are associated with HAEs, demonstrating the potential of tracing SMG counterparts with this population. To summarize, our results demonstrate that submillimeter observations may enable us to study (proto)clusters of massive, dusty starbursts.
- ID:
- ivo://CDS.VizieR/J/ApJ/907/123
- Title:
- Spin Parity of Spiral Galaxies. III.
- Short Name:
- J/ApJ/907/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is a revised catalog of spiral winding direction of SDSS spiral galaxies published by Shamir (2017PASA...34...11S). Whether the spiral pattern as projected on the sky is S-wise or Z-wise (Shamir called them counter clock wise and clockwise, respectively) can be an unambiguous tool to identify whether the galaxy spin vector is pointing toward or away from us as all the spirals are safely regarded as trailing spirals (Iye et al., 2019ApJ...886..113S). We used Shamir's catalog to analyze the dipole anisotropy in their large-scale structure and found that there exist rather massive duplicated entries and a few other minor errors in the original catalog. In this revised version those duplicated entries are cleaned keeping the judgment of the spiral winding direction due to Shamir (2017PASA...34...11S) except for a several obviously inconsistent cases. These corrections were necessary to make analysis of the large scale distribution of spin vectors of galaxies of the SDSS sample in our paper.
