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15091. Survey of Galactic Center region at 20cm
ID:
ivo://CDS.VizieR/J/ApJS/155/421
Title:
Survey of Galactic Center region at 20cm
Short Name:
J/ApJS/155/421
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is the first in a series of papers presenting a sensitive 20cm VLA continuum survey of the Galactic center region using new and archival data based on multiconfiguration observations taken with relatively uniform uv coverage. The high dynamic range images cover the regions within -2{deg}<l<5{deg} and -40'<b<40' with a spatial resolution of ~30" and 10". The wide field imaging technique is used to construct a low-resolution mosaic of 40 overlapping pointings. The mosaic image includes the Effelsberg observations filling the low spatial frequency uv data. We also present high-resolution images of 23 overlapping fields using DnC and CnB array configurations. These high-resolution images are sensitive to both compact and extended continuum features with a wide range of angular scales with rms noise of 0.2mJy/beam in the outer parts of the Galactic center region. The survey has resulted in a catalog of 345 discrete sources as well as 140 images revealing structural details of HII regions, supernova remnants, pulsar wind nebulae, and more than 80 linear filaments distributed toward the complex region of the Galactic center.
15092. Survey of galaxies within nearby voids. II
ID:
ivo://CDS.VizieR/J/AJ/119/32
Title:
Survey of galaxies within nearby voids. II
Short Name:
J/AJ/119/32
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze the optical properties of {~}300 galaxies within and around three prominent voids of the Center for Astrophysics Redshift Survey. We determine CCD morphologies and H{alpha} equivalent widths from our imaging and spectroscopic survey. We also describe a redshift survey of 250 neighboring galaxies in the imaging survey fields. We assess the morphology-density relation, EW(H{alpha})-density relation, and the effects of nearby companions for galaxies in low-density environments selected with a smoothed large-scale (5 h^-1^ Mpc) galaxy number density n.
15093. Survey of galaxies within prominent nearby voids
ID:
ivo://CDS.VizieR/J/AJ/118/2561
Title:
Survey of galaxies within prominent nearby voids
Short Name:
J/AJ/118/2561
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the optical properties of a large sample of galaxies in low-density regions of the nearby universe. We make a 5 h^-1^ Mpc smoothed map of the galaxy density throughout the Center for Astrophysics Redshift Survey (CfA2) to identify galaxies within three prominent nearby "voids" with diameter {>=} 30 h^-1^ Mpc. We augment the CfA2 void galaxy sample with fainter galaxies found in the same regions from the more recent and deeper Century and Redshift surveys. We obtain B and R CCD images and high signal-to-noise long-slit spectra for the resulting sample of 149 void galaxies, as well as for an additional 131 galaxies on the periphery of these voids. Here we describe the photometry for the sample, including B isophotal magnitudes and B-R colors.
15094. Survey of infall motions toward starless cores
ID:
ivo://CDS.VizieR/J/ApJ/526/788
Title:
Survey of infall motions toward starless cores
Short Name:
J/ApJ/526/788
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first results of a survey of 220 starless cores selected primarily by their optical obscuration and observed in CS (2-1), N_2_H^+^ (1-0), and C^18^O (1-0) using the Northeast Radio Observatory Corporation (NEROC) Haystack 37 m telescope. We have detected 163 out of 196 sources observed in CS, 72 out of 142 in N_2_H^+^, and 30 out of 30 in C18O. In total, 69 sources were detected in both CS and N_2_H^+^. The isolated component of the N_2_H^+^ (1-0) spectrum (F_1_F = 0,1-1,2) usually shows a weak symmetric profile that is optically thin. In contrast, a significant fraction of the CS spectra show non-Gaussian shapes, which we interpret as arising from a combination of self-absorption due to lower excitation gas in the core front and kinematics in the core. The distribution of the normalized velocity difference ({delta}V_CS_) between the CS and N_2_H^+^ peaks appears significantly skewed to the blue (V_CS_ < 0), as was found in a similar study of dense cores with embedded young stellar objects (YSOs). The incidence of sources with blue asymmetry tends to increase as the total optical depth or the integrated intensity of the N_2_H^+^ line increases.
15095. Survey of Interstellar clouds in the Gould belt
ID:
ivo://CDS.VizieR/J/ApJ/680/495
Title:
Survey of Interstellar clouds in the Gould belt
Short Name:
J/ApJ/680/495
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present observations of two areas totalling 0.57deg^2^ in the IC 5146 star-forming region at 3.6, 4.5, 5.8, 8.0, 24, and 70um observed with the Spitzer Space Telescope. We reexamine the issue of the distance to this cloud and conclude a value of 950+/-80pc is most likely. We compare source counts, colors, and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. We identify more than 200 young stellar object (YSO) candidates from color-magnitude and color-color diagrams, many of which were previously unknown. We compare the colors of these YSOs to the models of Robitaille et al. and perform simple fits to the SED's to estimate properties of the circumstellar disks likely to surround the Class II and III sources. We also compare the mid-IR disk excesses to H{alpha} emission-line data where available. We present a quantitative description of the degree of clustering, estimate the star formation efficiency, and discuss the fraction of YSOs in the region with disks relative to an estimate of the diskless YSO population. Finally, we compare the YSO distribution to the cold dust distribution mapped by SCUBA and briefly describe the diffuse emission likely due to PAHs associated with the HII region.
15096. Survey of low-redshift OVI absorbers
ID:
ivo://CDS.VizieR/J/ApJS/177/39
Title:
Survey of low-redshift OVI absorbers
Short Name:
J/ApJS/177/39
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using high-resolution ultraviolet spectra of 16 low-z QSOs obtained with the E140M echelle mode of the Space Telescope Imaging Spectrograph, we study the physical conditions and statistics of OVI absorption in the intergalactic medium (IGM) at z<0.5. We identify 51 intervening (z_abs_<z_QSO_) OVI systems comprising 77 individual components, and we find 14 "proximate" systems (z_abs_~z_QSO_) containing 34 components. For intervening systems (components) with rest-frame equivalent width W_r_>30m{AA}, the number of OVI absorbers per unit redshift dN/dz=15.6^+2.9^_-2.4_(21.0^+3.2^_-2.8_), and this decreases to dN/dz=0.9^+1.0^_-0.5_(0.3^+0.7^_-0.3_) for W_r_>300m{AA}. The number per redshift increases steeply as z_abs_ approaches z_QSO_; we find that dN/dz is ~3-10 times higher within 2500km/s of z_QSO_. The most striking difference between intervening and proximate systems is that some proximate absorbers have substantially lower HI/OVI ratios.
15097. Survey of M31 with Spitzer
ID:
ivo://CDS.VizieR/J/ApJ/687/230
Title:
Survey of M31 with Spitzer
Short Name:
J/ApJ/687/230
Date:
21 Oct 2021
Publisher:
CDS
Description:
We explore the stellar population of M31 in a Spitzer Space Telescope survey utilizing IRAC and MIPS observations. Red supergiants are the brightest objects seen in the infrared; they are a prominent evolutionary phase. Due to their circumstellar envelopes, many of these radiate the bulk of their luminosity at IRAC wavelengths and do not stand out in the near-infrared or optically. Going fainter, we see large numbers of luminous asymptotic giant branch stars (AGB), many of which are known long-period variables. Relative to M33 the AGB carbon star population of M31 appears sparse, but this needs to be spectroscopically confirmed.
15098. Survey of novae in M31
ID:
ivo://CDS.VizieR/J/ApJ/734/12
Title:
Survey of novae in M31
Short Name:
J/ApJ/734/12
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results of a multi-year spectroscopic and photometric survey of novae in M31 that resulted in a total of 53 spectra of 48 individual nova candidates. Two of these, M31N 1995-11e and M31N 2007-11g, were revealed to be long-period Mira variables, not novae. These data double the number of spectra extant for novae in M31 through the end of 2009 and bring to 91 the number of M31 novae with known spectroscopic classifications. We find that 75 novae (82%) are confirmed or likely members of the FeII spectroscopic class, with the remaining 16 novae (18%) belonging to the He/N (and related) classes. These numbers are consistent with those found for Galactic novae. We find no compelling evidence that spectroscopic class depends sensitively on spatial position or population within M31 (i.e., bulge versus disk), although the distribution for He/N systems appears slightly more extended than that for the FeII class. We confirm the existence of a correlation between speed class and ejection velocity (based on line width), as in the case of Galactic novae. Follow-up photometry allowed us to determine light-curve parameters for a total of 47 of the 91 novae with known spectroscopic class. We confirm that more luminous novae generally fade the fastest and that He/N novae are typically faster and brighter than their FeII counterparts. In addition, we find a weak dependence of nova speed class on position in M31, with the spatial distribution of the fastest novae being slightly more extended than that of slower novae.
15099. Survey of optically variables QSOs
ID:
ivo://CDS.VizieR/J/A+A/296/665
Title:
Survey of optically variables QSOs
Short Name:
J/A+A/296/665
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe a survey for variable QSOs carried out for 15 years with the UK Schmidt telescope, using IIIaJ plates exposed behind a Schott GG395 filter. Objects brighter than B=21.0 on a reference plate and displaying a peak to peak amplitude of variability larger than B=0.35mag are selected. Plates in U, V, R and I were also obtained.
15100. Survey of SiO maser emission in oxygen-rich stars
ID:
ivo://CDS.VizieR/J/ApJS/253/44
Title:
Survey of SiO maser emission in oxygen-rich stars
Short Name:
J/ApJS/253/44
Date:
01 Mar 2022 00:16:35
Publisher:
CDS
Description:
Circumstellar environments of oxygen-rich stars are among the strongest SiO maser emitters. Physical processes such as collisions, infrared pumping, and overlaps favor the inversion of level population and produce maser emission at different vibrational states. Despite numerous observational and theoretical efforts, we still do not have a unified picture including all of the physical processes involved in SiO maser emission. The aim of this work is to provide homogeneous data in a large sample of oxygen-rich stars. We present a survey of 67 oxygen-rich stars from 7 to 1mm, in their rotational transitions from J=1-0 to J=5-4, for vibrational numbers v from 0 to 6 in the three main SiO isotopologs. We have used one of the 34 m NASA antennas at Robledo and the IRAM 30m radio telescope. The first tentative detection of a v=6 line is reported, as well as the detection of new maser lines. The highest vibrational levels seem confined to small volumes, presumably close to the stars. The J=1-0, v=2 line flux is greater than the corresponding v=1 in almost half of the sample, which may confirm a predicted dependence on the pulsation cycle. This database is potentially useful in models which should consider most of the physical agents, time dependency, and mass-loss rates. As a by-product, we report detections of 27 thermal rotational lines from other molecules, including isotopologs of SiS, H_2_S, SO, SO_2_, and NaCl.

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