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3101. Colour magnitude diagram of M13
ID:
ivo://CDS.VizieR/J/A+AS/102/397
Title:
Colour magnitude diagram of M13
Short Name:
J/A+AS/102/397
Date:
21 Oct 2021
Publisher:
CDS
Description:
Two overlapping regions of M13 were observed on April 24, 1989 at the Loiano Observatory with a CDCD camera. A Colour-Magnitude diagram down to the main sequence was derived, as a preliminary search for the blue Horizontal Branch stars in this cluster.
3102. Colours and H{alpha} in galaxy pairs
ID:
ivo://CDS.VizieR/J/ApJ/582/668
Title:
Colours and H{alpha} in galaxy pairs
Short Name:
J/ApJ/582/668
Date:
21 Oct 2021
Publisher:
CDS
Description:
Galaxy-galaxy interactions rearrange the baryons in galaxies and trigger substantial star formation; the aggregate effects of these interactions on the evolutionary histories of galaxies in the universe are poorly understood. We combine B- and R-band photometry and optical spectroscopy to estimate the strengths and timescales of bursts of triggered star formation in the centers of 190 galaxies in pairs and compact groups. Based on an analysis of the measured colors and EW(H{alpha}), we characterize the preexisting and triggered populations separately. The best-fitting burst scenarios assume stronger reddening corrections for line emission than for the continuum and continuous star formation lasting for >~100Myr. The most realistic scenarios require an initial mass function that is deficient in the highest mass stars. The color of the preexisting stellar population is the most significant source of uncertainty. Triggered star formation contributes substantially (probably >~50%) to the R-band flux in the central regions of several galaxies; tidal tails do not necessarily accompany this star formation. Many of the galaxies in our sample have bluer centers than outskirts, suggesting that pre- or nonmerger interactions may lead to evolution along the Hubble sequence. These objects would appear blue and compact at higher redshifts; the older, redder outskirts of the disks would be difficult to detect. Our data indicate that galaxies with larger separations on the sky contain weaker, and probably older, bursts of star formation on average. However, confirmation of these trends requires further constraints on the colors of the older stellar populations and on the reddening for individual galaxies.
3103. Colours and HI line observations in Virgo
ID:
ivo://CDS.VizieR/J/MNRAS/357/819
Title:
Colours and HI line observations in Virgo
Short Name:
J/MNRAS/357/819
Date:
21 Oct 2021
Publisher:
CDS
Description:
In order to investigate the nature of dwarf low surface brightness (LSB) galaxies we have undertaken a deep B- and I-band CCD survey of a 14-deg^2^ strip in the Virgo Cluster and applied a Fourier convolution technique to explore its dwarf galaxy population down to a central surface brightness of ~26Bmag/arcsec^2^ and a total absolute B magnitude of ~-10. In this paper we carry out an analysis of their morphology, (B-I) colours and atomic hydrogen content.
3104. Colours of z~6 galaxies in GOODS
ID:
ivo://CDS.VizieR/J/ApJ/600/L99
Title:
Colours of z~6 galaxies in GOODS
Short Name:
J/ApJ/600/L99
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report early results on galaxies at z~6 selected from Hubble Space Telescope imaging for the Great Observatories Origins Deep Survey. Spectroscopy of one object with the Advanced Camera for Surveys grism and from the Keck and Very Large Telescope observatories shows a strong continuum break and asymmetric line emission, identified as Ly{alpha} at z=5.83. We find only five spatially extended candidates with signal-to-noise ratios greater than 10, two of which have spectroscopic confirmation. This is much fewer than would be expected if galaxies at z=6 had the same luminosity function as those at z=3. There are many fainter candidates, but we expect substantial contamination from foreground interlopers and spurious detections. Our best estimates favor a z=6 galaxy population with fainter luminosities, higher space density, and similar comoving ultraviolet emissivity to that at z=3, but this depends critically on counts at fluxes fainter than those reliably probed by the current data.
3105. Column densities for HI, AlIII, SiIV, CIV, OVI
ID:
ivo://CDS.VizieR/J/ApJ/702/1472
Title:
Column densities for HI, AlIII, SiIV, CIV, OVI
Short Name:
J/ApJ/702/1472
Date:
21 Oct 2021
Publisher:
CDS
Description:
Column densities for HI, AlIII, SiIV, CIV, and OVI toward 109 stars and 30 extragalactic objects have been assembled to study the extensions of these species away from the Galactic plane into the Galactic halo. HI and AlIII mostly trace the warm neutral and warm ionized medium, respectively, while SiIV, CIV, and OVI trace a combination of warm photoionized and collisionally ionized plasmas. The much larger object sample compared to previous studies allows us to consider and correct for the effects of the sample bias that has affected earlier but smaller surveys of the gas distributions. The observations are compared to the predictions of the various models for the production of the transition temperature gas in the halo.
3106. Column densities from HST/COS SiIV AGN sight lines
ID:
ivo://CDS.VizieR/J/ApJ/894/142
Title:
Column densities from HST/COS SiIV AGN sight lines
Short Name:
J/ApJ/894/142
Date:
19 Jan 2022 13:10:08
Publisher:
CDS
Description:
We develop a kinematical model for the Milky Way SiIV-bearing gas to determine its density distribution and kinematics. This model is constrained by a column density line-shape sample extracted from the Hubble Space Telescope/Cosmic Origins Spectrograph archival data, which contains 186 active galactic nucleus sight lines. We find that the SiIV ion density distribution is dominated by an extended disk along the z-direction (above or below the midplane), i.e., n(z)=n_0_exp(-(z/z_0_)^0.82^), where z_0_ is the scale height of 6.3_-1.5_^+1.6^kpc (northern hemisphere) and 3.6_-0.9_^+1.0^kpc (southern hemisphere). The density distribution of the disk in the radial direction shows a sharp edge at 15-20kpc given by, n(r_XY_)=n_0_exp(-(r_XY_/r_0_)^3.36^), where r_0_~12.5+/-0.6kpc. The difference of density distributions over r_XY_ and z directions indicates that the warm gas traced by SiIV is mainly associated with disk processes (e.g., feedback or cycling gas) rather than accretion. We estimate the mass of the warm gas (within 50kpc) is log(M(50kpc)/M_{sun}_)~8.1 (assuming Z~0.5Z_{sun}_), and a 3{sigma} upper limit of log(M(250kpc)/M_{sun}_)~9.1 (excluding the Magellanic system). Kinematically, the warm gas disk is nearly co-rotating with the stellar disk at v_rot_=215+/-3km/s, which lags the midplane rotation by about 8km/s/kpc (within 5kpc). Meanwhile, we note that the warm gas in the northern hemisphere has significant accretion with vacc of 69+/-7km/s at 10kpc (an accretion rate of -0.60_-0.13_^+0.11^M_{sun}_/yr), while in the southern hemisphere, there is no measurable accretion, with an upper limit of 0.4M_{sun}_/yr.
3107. Column densities of CGM absorption lines
ID:
ivo://CDS.VizieR/J/ApJ/883/78
Title:
Column densities of CGM absorption lines
Short Name:
J/ApJ/883/78
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the geometric distribution of gas metallicities in the circumgalactic medium (CGM) around 47, z<0.7 galaxies from the "Multiphase Galaxy Halos" Survey. Using a combination of quasar spectra from Hubble Space Telescope (HST)/COS and from Keck/HIRES or Very Large Telescope/UVES, we measure column densities of, or determine limits on, CGM absorption lines. We then use a Markov Chain Monte Carlo approach with Cloudy to estimate the metallicity of cool (T~10^4^K) CGM gas. We also use HST images to determine host-galaxy inclination and quasar-galaxy azimuthal angles. Our sample spans a HI column density range of 13.8cm^-2^<logN_HI_<19.9cm^-2^. We find (1) while the metallicity distribution appears bimodal, a Hartigan dip test cannot rule out a unimodal distribution (0.4{sigma}). (2) CGM metallicities are independent of halo mass, spanning three orders of magnitude at a fixed halo mass. (3) The CGM metallicity does not depend on the galaxy azimuthal and inclination angles regardless of HI column density, impact parameter, and galaxy color. (4) The ionization parameter does not depend on azimuthal angle. We suggest that the partial Lyman limit metallicity bimodality is not driven by a spatial azimuthal bimodality. Our results are consistent with simulations where the CGM is complex and outflowing, accreting, and recycled gas are well-homogenized at z<0.7. The presence of low-metallicity gas at all orientations suggests that cold streams of accreting filaments are not necessarily aligned with the galaxy plane at low redshifts or intergalactic transfer may dominate. Finally, our results support simulations showing that strong metal absorption can mask the presence of low-metallicity gas in integrated line-of-sight CGM metallicities.
3108. Column density maps in 4 IRDCs
ID:
ivo://CDS.VizieR/J/A+A/578/A29
Title:
Column density maps in 4 IRDCs
Short Name:
J/A+A/578/A29
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyse column density and temperature maps derived from Herschel dust continuum observations of a sample of prominent, massive infrared dark clouds (IRDCs) i.e. G11.11-0.12, G18.82-0.28, G28.37+0.07, and G28.53-0.25. We disentangle the velocity structure of the clouds using ^13^CO 1->0 and ^12^CO 3->2 data, showing that these IRDCs are the densest regions in massive giant molecular clouds (GMCs) and not isolated features. The probability distribution function (PDF) of column densities for all clouds have a power-law distribution over all (high) column densities, regardless of the evolutionary stage of the cloud: G11.11-0.12, G18.82-0.28, and G28.37+0.07 contain (proto)-stars, while G28.53-0.25 shows no signs of star formation. This is in contrast to the purely log-normal PDFs reported for near and/or mid-IR extinction maps. We only find a log-normal distribution for lower column densities, if we perform PDFs of the column density maps of the whole GMC in which the IRDCs are embedded. By comparing the PDF slope and the radial column density profile of three of our clouds, we attribute the power law to the effect of large-scale gravitational collapse and to local free-fall collapse of pre- and protostellar cores for the highest column densities. A significant impact on the cloud properties from radiative feedback is unlikely because the clouds are mostly devoid of star formation. Independent from the PDF analysis, we find infall signatures in the spectral profiles of ^12^CO for G28.37+0.07 and G11.11-0.12, supporting the scenario of gravitational collapse. Our results are in line with earlier interpretations that see massive IRDCs as the densest regions within GMCs, which may be the progenitors of massive stars or clusters. At least some of the IRDCs are probably the same features as ridges (high column density regions with N>10^23^cm^-2^ over small areas), which were defined for nearby IR-bright GMCs. Because IRDCs are only confined to the densest (gravity dominated) cloud regions, the PDF constructed from this kind of a clipped image does not represent the (turbulence dominated) low column density regime of the cloud.
3109. Coma Ber and a Neighbor Stellar Group tidal tails
ID:
ivo://CDS.VizieR/J/ApJ/877/12
Title:
Coma Ber and a Neighbor Stellar Group tidal tails
Short Name:
J/ApJ/877/12
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of tidal structures around the intermediate-aged (~700-800Myr), nearby (~85pc) star cluster Coma Berenices. The spatial and kinematic grouping of stars is determined with the Gaia DR2 parallax and proper motion data, by a clustering analysis tool, StarGO, to map 5D parameters (X, Y, Z, {mu}_{alpha}*cos{delta}, {mu}_{delta}_) onto a 2D neural network. A leading and a trailing tails, each with an extension of ~50pc are revealed for the first time around this disrupting star cluster. The cluster members, totaling to ~115^+5^_-3_M_{sun}_, are clearly mass segregated, and exhibit a flat mass function with {alpha}~0.79+/-0.16, in the sense of dN/dm{prop.to}m^-{alpha}^, where N is the number of member stars and m is stellar mass, in the mass range of m=0.25-2.51M_{sun}_. Within the tidal radius of ~6.9pc, there are 77 member candidates with an average position, i.e., as the cluster center, of RA=186.8110{deg}, and DE=25.8112{deg}, and an average distance of 85.8pc. Additional 120 member candidates reside in the tidal structures, i.e., outnumbering those in the cluster core. The expansion of escaping members lead to an anisotropy in the velocity field of the tidal tails. Our analysis also serendipitously uncovers an adjacent stellar group, part of which has been cataloged in the literature. We identify 218 member candidates, 10 times more than previously known. This star group is some 65pc away from, and ~400Myr younger than, Coma Ber, but is already at the final stage of disruption.
3110. Coma Berenices astrometric catalogue
ID:
ivo://CDS.VizieR/J/A+AS/136/307
Title:
Coma Berenices astrometric catalogue
Short Name:
J/A+AS/136/307
Date:
21 Oct 2021
Publisher:
CDS
Description:
A catalogue of stellar positions and proper motions down to the 14th photographic magnitude in the area of the open cluster in Coma Berenices is compiled from data of 12 different sources. The accuracy of the proper motion data is comparable to that of the Hipparcos Catalogue (Cat. <I/239>).

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