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91. M 31 Disk Chandra PHAT Survey: HST-Derived Star Formation History
ID:
ivo://nasa.heasarc/m31phatsfh
Title:
M 31 Disk Chandra PHAT Survey: HST-Derived Star Formation History
Short Name:
M31PHATSFH
Date:
14 Feb 2025
Publisher:
NASA/GSFC HEASARC
Description:
The X-ray source populations within galaxies are typically difficult to identify and classify with X-ray data alone. The authors break through this barrier by combining deep new Chandra ACIS-I observations with extensive Hubble Space Telescope (HST) imaging from the Panchromatic Hubble Andromeda Treasury (PHAT) of the M 31 disk. They detect 373 X-ray sources down to 0.35-8.0keV flux of 10<sup>-15</sup>erg/cm<sup>-2</sup>/s over 0.4deg<sup>2</sup>, 170 of which are reported for the first time. The authors identify optical counterpart candidates for 188 of the 373 sources, after using the HST data to correct the absolute astrometry of our Chandra imaging to 0.1". These data are available at <a href="/W3Browse/chandra/m31phatcxo.html">M31PHATCXO</a>. For point-like counterparts, the authors examine the star formation history of the surrounding stellar populations to look for a young component that could be associated with a high-mass X-ray binary. This table presents the star formation histories for a subset of sources in the <a href="/W3Browse/chandra/m31phatcxo.html">M31PHATCXO catalog</a>. About one-third of the point sources are not physically associated with a young population, and are therefore more likely to be background galaxies. For the 40 point-like counterpart candidates associated with young populations, the authors find that their age distribution has two peaks at 15-20Myr and 40-50Myr. Considering only the 8 counterpart candidates with typical high-mass main-sequence optical star colors, their age distribution peaks mimic those of the sample of 40. Finally, the authors find that intrinsic faintness, and not extinction, is the main limitation for finding further counterpart candidates. In 2015 October, the authors observed the Panchromatic Hubble Andromeda Treasury (PHAT) footprint with Chandra with 7 pointings. The footprints are overlaid on a GALEX NUV image of M 31, along with the corresponding HST coverage, in Figure 1 of the reference paper. At each pointing they observed for about 50 ks in VF mode (Chandra ObsID 17008 to 17014 spanning 2015 Oct 06 to 2015 Oct 26). This table was created by the HEASARC in April 2020 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/239/13">CDS Catalog J/ApJS/239/13</a> file table7.dat. This is a service provided by NASA HEASARC .
92. M 31 Disk Chandra PHAT Survey: X-Ray Source Catalog
ID:
ivo://nasa.heasarc/m31phatcxo
Title:
M 31 Disk Chandra PHAT Survey: X-Ray Source Catalog
Short Name:
M31PHATCXO
Date:
14 Feb 2025
Publisher:
NASA/GSFC HEASARC
Description:
The X-ray source populations within galaxies are typically difficult to identify and classify with X-ray data alone. The authors break through this barrier by combining deep new Chandra ACIS-I observations with extensive Hubble Space Telescope (HST) imaging from the Panchromatic Hubble Andromeda Treasury (PHAT) of the M 31 disk. They detect 373 X-ray sources down to 0.35-8.0keV flux of 10<sup>-15</sup>erg/cm<sup>-2</sup>/s over 0.4deg<sup>2</sup>, 170 of which are reported for the first time. The authors identify optical counterpart candidates for 188 of the 373 sources, after using the HST data to correct the absolute astrometry of our Chandra imaging to 0.1". While 58 of these 188 are associated with point sources potentially in M 31, over half (107) of the counterpart candidates are extended background galaxies, 5 are star clusters, 12 are foreground stars, and 6 are supernova remnants. Sources with no clear counterpart candidate are most likely to be undetected background galaxies and low-mass X-ray binaries in M 31. The hardest sources in the 1-8keV band tend to be matched to background galaxies. The 58 point sources that are not consistent with foreground stars are bright enough that they could be high-mass stars in M 31; however, all but 8 have optical colors inconsistent with single stars, suggesting that many could be background galaxies or binary counterparts. For point-like counterparts, the authors examine the star formation history of the surrounding stellar populations to look for a young component that could be associated with a high-mass X-ray binary. The associated star formation histories for sources in the catalog are available in the linked table <a href="/W3Browse/chandra/m31phatsfh.html">M31PHATSFH</a>. In 2015 October, the authors observed the Panchromatic Hubble Andromeda Treasury (PHAT) footprint with Chandra with 7 pointings. The footprints are overlaid on a GALEX NUV image of M 31, along with the corresponding HST coverage, in Figure 1 of the reference paper. At each pointing they observed for about 50ks in VF mode (Chandra ObsID 17008 to 17014 spanning 2015 Oct 06 to 2015 Oct 26). This table was created by the HEASARC in April 2020 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/239/13">CDS Catalog J/ApJS/239/13</a> file table4.dat and table6.dat. This is a service provided by NASA HEASARC .
93. Morphological Types in 10 Distant Rich Clusters
ID:
ivo://CDS.VizieR/J/ApJS/110/213
Title:
Morphological Types in 10 Distant Rich Clusters
Short Name:
J/ApJS/110/213
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present catalogs of objects detected in deep images of 11 fields in 10 distant clusters obtained using WFPC-2 on board the Hubble Space Telescope. The clusters span the redshift range z=0.37-0.56 and are the subject of a detailed ground- and space-based study to investigate the evolution of galaxies as a function of environment and epoch. The data presented here include positions, photometry and basic morphological information on ~9000 objects in the fields of the 10 clusters. For a brighter subset of 1857 objects in these areas, we provide more detailed morphological information.
94. Morphologies of distant galaxies II
ID:
ivo://CDS.VizieR/J/ApJS/107/1
Title:
Morphologies of distant galaxies II
Short Name:
J/ApJS/107/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
The morphological properties of high-redshift galaxies are investigated using a sample of 507 objects (I<22.0mag) from the Hubble Space Telescope (HST) Medium Deep Survey. Independent visual morphological classifications for each galaxy are used to quantify the statistical uncertainties in the galaxy classifications. Visual classifications are found to agree well for I<21mag. Fainter than I=21mag significant disagreements are seen in the independent visual classifications of late-type systems with T>7, merging systems, and peculiar galaxies. The classifications of these systems are shown to be somewhat subjective. Objective classifications based upon measurements of central concentration and asymmetry for the Medium Deep Survey sample are presented. These classifications are calibrated using measurements of structural parameters for an artificially redshifted sample of local objects. Morphologically segregated number counts using both sets of visual classifications and objective classifications support the conclusion that the observed galaxy counts agree with no-evolution predictions for the elliptical and spiral populations, as reported in Glazebrook et al. (1995MNRAS.275L..19G). A major conclusion is that the large overdensity of merging/ peculiar/ irregular galaxies relative to the predictions of no-evolution models (reported by Glazebrook et al. 1995MNRAS.275L..19G) is confirmed. However, the shape of the faint-end (I>21.0mag) number count relation for peculiar objects is sensitive to the large systematic uncertainties inherent in the visual classification of these objects. Despite this caveat, the frequency of objects showing clear evidence for tidal interactions (e.g., tidal tails) in the HST sample is at least 50% larger than it is among nearby galaxies, at the 2{sigma} level. Relatively few "chain galaxies" are seen among the sample of peculiar objects, suggesting that these systems do not form a large component of the peculiar galaxy population at I<22mag.
95. M30 UBV photometry
ID:
ivo://CDS.VizieR/J/AJ/116/1757
Title:
M30 UBV photometry
Short Name:
J/AJ/116/1757
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present F555W (V), F439W (B), and F336W (U) photometry of 9507 stars in the central 2' of the dense, post-core-collapse cluster M30 (NGC 7099) derived from Hubble Space Telescope Wide Field Planetary Camera 2 images. These data are used to study the mix of stellar populations in the central region of the cluster. Forty-eight blue straggler stars are identified; they are found to be strongly concentrated toward the cluster center. The specific frequency of blue stragglers, F_BSS_=N(BSS)/N(V<V_HB_+2), is 0.25+/-0.05 in the inner region of M30 (r<20"), significantly higher than the frequency found in other clusters: F_BSS_=0.05-0.15. The shape of M30's blue straggler luminosity function resembles the prediction of the collisional formation model, and is inconsistent with the binary merger model of Bailyn & Pinsonneault (1995ApJ...439..705B). An unusually blue star (B=18.6, B-V=-0.97), possibly a cataclysmic variable based on its color, is found about 1.2" from the crowded cluster center; the photometric uncertainty for this star is large, however, because of the presence of a very close neighbor. Bright red giant stars (B<16.6) appear to be depleted by a factor of 2-3 in the inner r<10" relative to fainter giants, subgiants, and main-sequence turnoff stars (95% significance). We confirm that there is a radial gradient in the color of the overall cluster light, going from B-V~0.82 at r~1' to B-V~0.45 in the central 10". The central depletion of the bright red giants is responsible for about half of the observed color gradient; the rest of the gradient is caused by the relative underabundance of faint red main-sequence stars near the cluster center (presumably a result of mass segregation). The luminosity function of M30's evolved stars does not match the luminosity function shape derived from standard stellar evolutionary models: the ratio of the number of bright giants to the number of turnoff stars in the cluster is 30% higher than predicted by the model (3.8{sigma} effect), roughly independent of red giant brightness over the range M_V_=-2 to +2.
96. Multicolor photometry in NGC 1512 and NGC 5248
ID:
ivo://CDS.VizieR/J/AJ/121/3048
Title:
Multicolor photometry in NGC 1512 and NGC 5248
Short Name:
J/AJ/121/3048
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present broadband (U, V, I, and H) and narrowband (H{alpha}+[N II] and Pa{alpha}) images of the circumnuclear starburst rings in two nearby spiral galaxies, NGC 1512 and NGC 5248, obtained with the WFPC2 and NICMOS cameras on HST. Combined with previously published ultraviolet (UV) HST images at 2300{AA} these data provide a particularly wide wavelength range with which to study the properties of the stellar populations, the gas, and the dust in the rings.
97. Nearby Ly{alpha} quasar absorbers
ID:
ivo://CDS.VizieR/J/ApJ/524/536
Title:
Nearby Ly{alpha} quasar absorbers
Short Name:
J/ApJ/524/536
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spectroscopy of 10 quasars obtained with the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) is presented. In the 10 sight lines, we detect 357 absorption lines above a significance level of 3{sigma} and 272 lines above a significance level of 4.5{sigma}. Automated software is used to detect and identify the lines, almost all of which are unresolved at the GHRS G140L resolution of 200km/s. After identifying Galactic lines, intervening metal lines, and higher order Lyman lines, we are left with 139 Ly{alpha} absorbers in the redshift range 0<z<0.22 (lines within 900km/s of geocoronal Ly{alpha} are not selected). These diffuse hydrogen absorbers have column densities that are mostly in the range 10^13^-10^15^cm^-2^ for an assumed Doppler parameter of 30km/s. The number density of lines above a rest equivalent width of 0.24{AA}, dN/dz=38.3{+/-}5.3, agrees well with the measurement from the Quasar Absorption-Line Key Project. There is marginal evidence for cosmic variance in the number of absorbers detected among the 10 sight lines.
98. Near Infrared Camera and Multi Object Spectrograph
ID:
ivo://archive.stsci.edu/hst/nicmos
Title:
Near Infrared Camera and Multi Object Spectrograph
Short Name:
HST.NICMOS
Date:
23 Jul 2020 19:50:23
Publisher:
Space Telescope Science Institute Archive
Description:
The HST Near Infrared Camera and Multi-Object Spectrometer (NICMOS) provides imaging capabilities in broad, medium, and narrow band filters, broad-band imaging polarimetry, coronographic imaging, and slitless grism spectroscopy, in the wavelength range 0.8-2.5 microns. NICMOS has three adjacent but not contiguous cameras, designed to operate independently, each with a dedicated array at a different magnification scale.
99. New double stars from HST
ID:
ivo://CDS.VizieR/J/PASP/110/1012
Title:
New double stars from HST
Short Name:
J/PASP/110/1012
Date:
21 Oct 2021
Publisher:
CDS
Description:
Data from the Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) interferometers, covering 22 months of guide-star acquisition operations, have been analyzed for evidence of stellar duplicity. The data comprise a survey of observed guide stars, all of which are taken from the HST Guide Star Catalog, ranging in magnitude from 9 to 14. The survey results cover a parameter space for the newly found doubles, for the fainter stars, which are of smaller limiting angular separations than in any previous surveys. The normal HST engineering telemetry data from 13,979 acquisitions on 4882 stars have been processed. The FGS guidance data can reveal duplicity with separations ranging from approximately 30mas, for the brighter stars, with small magnitude differences, up to the neighborhood of 500mas, and in some cases to 1000mas. The fraction of guide stars indicating duplicity is a function of the statistical criteria used but is over 5% at a very high level of confidence. It is possible that if some of the brighter and closer pairs could be identified as nearby, then their orbital motions would be rapid enough to allow a mass and distance determination on a timescale of a decade if followed with ground-based interferometric and spectroscopic instruments. A brief catalog of doubles is given, nearly all of which are of certain duplicity. Information for accessing on-line catalogs of large numbers of stars with lesser, but nevertheless strong, probabilities of duplicity and also for the solutions for duplicity from all acquisitions is provided.
100. NGC 1741 HST photometry
ID:
ivo://CDS.VizieR/J/AJ/117/1708
Title:
NGC 1741 HST photometry
Short Name:
J/AJ/117/1708
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use Hubble Space Telescope (HST) Faint Object Camera (FOC) ultraviolet (UV) and WFPC2 optical images in conjunction with UV spectroscopic observations taken with the Goddard High Resolution Spectrograph to examine the star formation history and properties of the interacting galaxy system NGC 1741 in the Hickson Compact Group 31. The high spatial resolution afforded by HST has allowed us to identify a large number of starburst knots, or "superstar clusters" (SSCs), in the starburst regions of this system. Photometry of these SSCs in the UV and optical bands indicates that most of these objects have ages of a few Myr, with a few up to ~100Myr, and masses between 10^4^ and 10^6^M_{sun}_. The estimated age is confirmed by a spectral synthesis analysis of one knot for which we have obtained a UV spectrum. The V-band luminosity function of the SSCs is well represented by a power law {Phi}(L)~L^-{alpha}^ with an index of -1.85, with no evidence of a turnover brighter than the completeness limit. These properties are in good agreement with those found for SSCs in other starburst galaxies. Our results support the suggestion that some of these SSCs may be extremely young globular clusters formed in a relatively recent starburst episode that has been triggered by a merger event.