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3171. ~30yr of opt. spectroscopy & Vmag obs. of GW Ori
ID:
ivo://CDS.VizieR/J/ApJ/851/132
Title:
~30yr of opt. spectroscopy & Vmag obs. of GW Ori
Short Name:
J/ApJ/851/132
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present spatially and spectrally resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of gas and dust orbiting the pre-main-sequence hierarchical triple-star system GW Ori. A forward modeling of the ^13^CO and C^18^O J=2-1 transitions permits a measurement of the total stellar mass in this system, 5.29+/-0.09M_{sun}_, and the circumtriple disk inclination, 137.6{deg}+/-2.0{deg}. Optical spectra spanning a 35yr period were used to derive new radial velocities and, coupled with a spectroscopic disentangling technique, revealed that the A and B components of GW Ori form a double-lined spectroscopic binary with a period of 241.50+/-0.05d; a tertiary companion orbits that inner pair with a period of 4218+/-50d. Combining the results from the ALMA data and the optical spectra with three epochs of astrometry in the literature, we constrain the individual stellar masses in the system (M_A_~2.7M_{sun}_, M_B_~1.7M_{sun}_, M_C_~0.9M_{sun}_) and find strong evidence that at least one of the stellar orbital planes (and likely both) is misaligned with the disk plane by as much as 45{deg}. A V-band light curve spanning 30yr reveals several new ~30-day eclipse events 0.1-0.7mag in depth and a 0.2mag sinusoidal oscillation that is clearly phased with the AB-C orbital period. Taken together, these features suggest that the A-B pair may be partially obscured by material in the inner disk as the pair approaches apoastron in the hierarchical orbit. Lastly, we conclude that stellar evolutionary models are consistent with our measurements of the masses and basic photospheric properties if the GW Ori system is ~1Myr old.
3172. YSOs in the Serpens Molecular Cloud
ID:
ivo://CDS.VizieR/J/ApJ/714/778
Title:
YSOs in the Serpens Molecular Cloud
Short Name:
J/ApJ/714/778
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Spitzer InfraRed Spectrograph (IRS) mid-infrared (5-35um) spectra of a complete flux-limited sample (>=3mJy at 8um) of young stellar object (YSO) candidates selected on the basis of their infrared colors in the Serpens Molecular Cloud. Spectra of 147 sources are presented and classified. Background stars (with slope consistent with a reddened stellar spectrum and silicate features in absorption), galaxies (with redshifted polycyclic aromatic hydrocarbon (PAH) features), and a planetary nebula (with high ionization lines) amount to 22% of contamination in this sample, leaving 115 true YSOs. Sources with rising spectra and ice absorption features, classified as embedded Stage I protostars, amount to 18% of the sample. The remaining 82% (94) of the disk sources are analyzed in terms of spectral energy distribution shapes, PAHs, and silicate features. The presence, strength, and shape of these silicate features are used to infer disk properties for these systems. About 8% of the disks have 30/13um flux ratios consistent with cold disks with inner holes or gaps, and 3% of the disks show PAH emission.
3173. YSOs search in LDN 1340 in optical
ID:
ivo://CDS.VizieR/J/ApJ/822/79
Title:
YSOs search in LDN 1340 in optical
Short Name:
J/ApJ/822/79
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have performed an optical spectroscopic and photometric search for young stellar objects associated with the molecular cloud Lynds 1340, and examined the structure of the cloud by constructing an extinction map, based on SDSS data. The new extinction map suggests a shallow, strongly fragmented cloud, having a mass of some 3700M_{sun}_. Longslit spectroscopic observations of the brightest stars over the area of L1340 revealed that the most massive star associated with L1340 is a B4-type, ~5M_{sun}_ star. The new spectroscopic and photometric data of the intermediate-mass members led to a revised distance of 825_-80_^+110^pc, and revealed seven members of the young stellar population with M>~2M_{sun}_. Our search for H{alpha} emission line stars, conducted with the Wide Field Grism Spectrograph 2 on the 2.2m telescope of the University of Hawaii and covering a 30'x40' area, resulted in the detection of 75 candidate low-mass pre-main sequence stars, 58 of which are new. We constructed spectral energy distributions (SEDs) of our target stars, based on SDSS, 2MASS, Spitzer, and WISE photometric data, derived their spectral types, extinctions, and luminosities from BVRIJ fluxes, estimated masses by means of pre-main sequence evolutionary models, and examined the disk properties utilizing the 2-24{mu}m interval of the SED. We measured the equivalent width of the H{alpha} lines and derived accretion rates. The optically selected sample of pre-main sequence stars has a median effective temperature of 3970K, a stellar mass of 0.7M_{sun}_, and an accretion rate of 7.6x10^-9^M_{sun}_/yr.
3174. z<0.06 active black hole galaxies from SDSS-DR8
ID:
ivo://CDS.VizieR/J/ApJ/775/116
Title:
z<0.06 active black hole galaxies from SDSS-DR8
Short Name:
J/ApJ/775/116
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a sample of 151 dwarf galaxies (10^8.5^<~M_*_<~10^9.5^M_{sun}_) that exhibit optical spectroscopic signatures of accreting massive black holes (BHs), increasing the number of known active galaxies in this stellar-mass range by more than an order of magnitude. Utilizing data from the Sloan Digital Sky Survey Data Release 8 and stellar masses from the NASA-Sloan Atlas, we have systematically searched for active BHs in ~25000 emission-line galaxies with stellar masses comparable to the Magellanic Clouds and redshifts z<0.055. Using the narrow-line [OIII]/H{beta} versus [NII]/H{alpha} diagnostic diagram, we find photoionization signatures of BH accretion in 136 galaxies, a small fraction of which also exhibit broad H{alpha} emission. For these broad-line active galactic nucleus (AGN) candidates, we estimate BH masses using standard virial techniques and find a range of 10^5^<~M_BH_<~10^6^M_{sun}_ and a median of M_BH_~2x10^5^M_{sun}_. We also detect broad H{alpha} in 15 galaxies that have narrow-line ratios consistent with star-forming galaxies. Follow-up observations are required to determine if these are true type 1 AGN or if the broad H{alpha} is from stellar processes. The median absolute magnitude of the host galaxies in our active sample is M_g_=-18.1mag, which is ~1-2mag fainter than previous samples of AGN hosts with low-mass BHs. This work constrains the smallest galaxies that can form a massive BH, with implications for BH feedback in low-mass galaxies and the origin of the first supermassive BH seeds.
3175. z<0.06 broad-line AGN emission-line measures
ID:
ivo://CDS.VizieR/J/ApJ/813/82
Title:
z<0.06 broad-line AGN emission-line measures
Short Name:
J/ApJ/813/82
Date:
21 Oct 2021
Publisher:
CDS
Description:
Scaling relations between central black hole (BH) mass and host galaxy properties are of fundamental importance to studies of BH and galaxy evolution throughout cosmic time. Here we investigate the relationship between BH mass and host galaxy total stellar mass using a sample of 262 broad-line active galactic nuclei (AGNs) in the nearby universe (z<0.055), as well as 79 galaxies with dynamical BH masses. The vast majority of our AGN sample is constructed using Sloan Digital Sky Survey spectroscopy and searching for Seyfert-like narrow-line ratios and broad H{alpha} emission. BH masses are estimated using standard virial techniques. We also include a small number of dwarf galaxies with total stellar masses M_stellar_<~10^9.5^M_{sun}_ and a subsample of the reverberation-mapped AGNs. Total stellar masses of all 341 galaxies are calculated in the most consistent manner feasible using color-dependent mass-to-light ratios. We find a clear correlation between BH mass and total stellar mass for the AGN host galaxies, with M_BH_{propto}M_stellar_, similar to that of early-type galaxies with dynamically detected BHs. However, the relation defined by the AGNs has a normalization that is lower by more than an order of magnitude, with a BH-to-total stellar mass fraction of M_BH_/M_stellar_~0.025% across the stellar mass range 10^8^<=M_stellar_/M_{sun}_<=10^12^. This result has significant implications for studies at high redshift and cosmological simulations in which stellar bulges cannot be resolved.
3176. z<0.16 CIV absorbers from HST/COS QSOs spectra
ID:
ivo://CDS.VizieR/J/ApJ/815/91
Title:
z<0.16 CIV absorbers from HST/COS QSOs spectra
Short Name:
J/ApJ/815/91
Date:
21 Oct 2021
Publisher:
CDS
Description:
To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium, we have conducted a blind survey for CIV absorption systems in 89 QSO sightlines observed with the Hubble Space Telescope Cosmic Origins Spectrograph. We have identified 42 absorbers at z<0.16, comprising the largest uniform blind sample size to date in this redshift range. Our measurements indicate an increasing CIV absorber number density per comoving path length (dN/dX=7.5+/-1.1) and modestly increasing mass density relative to the critical density of the universe ({Omega}_CIV_=10.0+/-1.5x10^-8^) from z~1.5 to the present epoch, consistent with predictions from cosmological hydrodynamical simulations. Furthermore, the data support a functional form for the column density distribution function that deviates from a single power law, also consistent with independent theoretical predictions. As the data also probe heavy element ions in addition to CIV at the same redshifts, we identify, measure, and search for correlations between column densities of these species where components appear to be aligned in velocity. Among these ion-ion correlations, we find evidence for tight correlations between CII and SiII, CII and SiIII, and CIV and SiIV, suggesting that these pairs of species arise in similar ionization conditions. However, the evidence for correlations decreases as the difference in ionization potential increases. Finally, when controlling for observational bias, we find only marginal evidence for a correlation (86.8% likelihood) between the Doppler line width b(CIV) and column density N(CIV).
3177. Z CMa NW emission lines
ID:
ivo://CDS.VizieR/J/A+A/643/A29
Title:
Z CMa NW emission lines
Short Name:
J/A+A/643/A29
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use optical spectroscopy to investigate the disk, wind, and accretion during the 2008 Z CMa NW outburst. The emission lines are used to constrain the locations, densities, and temperatures of the structures around the star. Over 1000 optical emission lines reveal accretion, a variable, multi-component wind, and double-peaked lines of disk origin. The variable, non-axisymmetric, accretion-powered wind has slow (~0km/s ), intermediate (~-100km/s) and fast (>=-400km/s) components. The fast components are of stellar origin and disappear in quiescence, while the slow component is less variable and could be related to a disk wind. The changes in the optical depth of the lines between outburst and quiescence are consistent with increased accretion being responsible for the observed outburst. We derive an accretion rate of 10^-4^M_{sun}_/yr in outburst. The FeI and weak FeII lines arise from an irradiated, flared disk at ~0.5-3(M*/16M_{sun}_) au with asymmetric upper layers, revealing that the energy from the accretion burst is deposited at scales below 0.5au. Some line profiles have redshifted asymmetries, but the system is unlikely sustained by magnetospheric accretion, especially in outburst. The accretion-related structures extend over several stellar radii and, like the wind, are likely non-axisymmetric. The stellar mass may be ~6-8M_{sun}_, lower than previously thought (~16M_{sun}_). Emission line analysis is found to be a powerful tool to study the innermost regions and accretion in stars within a very large range of effective temperatures. The density ranges in the disk and accretion structures are higher than in late-type stars, but the overall behavior, including the innermost disk emission and variable wind, is very similar independently of the spectral type. Our work suggests a common outburst behavior for stars with spectral types ranging from M-type to intermediate-mass stars.
3178. z~2.3 cosmic voids in the COSMOS field
ID:
ivo://CDS.VizieR/J/ApJ/861/60
Title:
z~2.3 cosmic voids in the COSMOS field
Short Name:
J/ApJ/861/60
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the most distant detection of cosmic voids (z~2.3) and the first detection of three-dimensional voids in the Ly{alpha} forest. We used a 3D tomographic map of the absorption with an effective comoving spatial resolution of 2.5h^-1^Mpc and a volume of 3.15x10^5^h^-3^Mpc^3^, which was reconstructed from moderate-resolution Keck I/LRIS spectra of 240 background Lyman-break galaxies and quasars in a 0.16deg^2^ footprint in the COSMOS field. Voids were detected using a spherical overdensity finder calibrated from hydrodynamical simulations of the intergalactic medium (IGM). This allows us to identify voids in the IGM corresponding to voids in the underlying matter density field, yielding a consistent volume fraction of voids in both data (19.5%) and simulations (18.2%). We fit excursion set models to the void radius function and compare the radially averaged stacked profiles of large voids (r>5h^-1^Mpc) to stacked voids in mock observations and the simulated density field. Comparing with 432 coeval galaxies with spectroscopic redshifts in the same volume as the tomographic map, we find that the tomography-identified voids are underdense in galaxies by 5.95{sigma} compared to random cells.
3179. zCosmos Bright Spectroscopic Observations DR2
ID:
ivo://org.gavo.dc/zcosmos/q/ssa
Title:
zCosmos Bright Spectroscopic Observations DR2
Short Name:
zCosmos SSAP
Date:
27 Dec 2024 08:31:03
Publisher:
The GAVO DC team
Description:
The zCOSMOS redshift survey used 600h on the VIMOS spectrograph spread over five observing seasons (2005-2009) to obtain spectra of about 20,000 galaxies selected to have Iab < 22.5 across the full 1.7 deg2 of the COSMOS field. This part, "zCOSMOS-bright", was designed to yield a high and fairly uniform sampling rate (about 70%), with a high success rate in measuring redshifts (approaching 100% at 0.5 < z < 0.8), and with sufficient velocity accuracy (about 100 km/s) to efficiently map the environments of galaxies down to the scale of galaxy groups out to redshifts z ~ 1.
3180. zCOSMOS 20k Bright - Simple Spectrum Access
ID:
ivo://lam.cesam.aspic/zcosmos_20k/q/ssa
Title:
zCOSMOS 20k Bright - Simple Spectrum Access
Short Name:
zCOSMOS SSAP
Date:
25 Aug 2021 00:22:43
Publisher:
The CeSAM VO team
Description:
Spectra from the third data release (DR3) of zCOSMOS 20k bright.

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