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4401. NGC 3610 globular clusters HST BVI photometry
ID:
ivo://CDS.VizieR/J/AJ/133/2737
Title:
NGC 3610 globular clusters HST BVI photometry
Short Name:
J/AJ/133/2737
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Advanced Camera for Surveys on board the Hubble Space Telescope has been used to obtain deep, high-resolution images of the giant elliptical galaxy NGC 3610, a well-established remnant of a dissipative galaxy merger. These observations supersede previous, shallower observations that revealed the presence of a population of metal-rich globular clusters of intermediate age (~1.5-4Gyr). We detect a total of 580 cluster candidates, 46% more than from the previous WFPC2 images. The new photometry strengthens the significance of the previously found bimodality of the color distribution of clusters.
4402. NGC 5128 globular clusters photometry
ID:
ivo://CDS.VizieR/J/AJ/140/2101
Title:
NGC 5128 globular clusters photometry
Short Name:
J/AJ/140/2101
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new photometry for 323 of the globular clusters in NGC 5128 (Centaurus A), measured for the first time in the g'r'i'z' filter system. The color indices are calibrated directly to standard stars in the g'r'i'z' system and are used to establish the fiducial mean colors for the blue and red (low and high metallicity) globular cluster sequences. We also use previously published spectroscopically measured abundances to establish the conversion between the most metallicity-sensitive colors ((g'-r')_0_,(g'-i')_0_) and metallicity, [Fe/H].
4403. NGC 5128 globular clusters UBVRICMT1 phot. & RV
ID:
ivo://CDS.VizieR/J/AJ/134/494
Title:
NGC 5128 globular clusters UBVRICMT1 phot. & RV
Short Name:
J/AJ/134/494
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new kinematic and dynamic study of the halo of the giant elliptical galaxy NGC 5128 is presented. From a spectroscopically confirmed sample of 340 globular clusters and 780 planetary nebulae, the rotation amplitude, rotation axis, velocity dispersion, and total dynamical mass are determined for the halo of NGC 5128.
4404. NGC 5523 H-band image
ID:
ivo://CDS.VizieR/J/A+A/598/A119
Title:
NGC 5523 H-band image
Short Name:
J/A+A/598/A119
Date:
21 Oct 2021
Publisher:
CDS
Description:
Multi-band images of the very isolated spiral galaxy NGC 5523 show a number of unusual features consistent with NGC 5523 having experienced a significant merger: (1) Near-infrared (NIR) images from the Spitzer Space Telescope (SST) and the WIYN 3.5-m Multi-band images of the very isolated spiral galaxy NGC 5523 show a number of unusual features consistent with NGC 5523 having experienced a significant merger: (1) Near-infrared (NIR) images from the Spitzer Space Telescope (SST) and the WIYN 3.5-m telescope reveal a nucleated bulge-like structure embedded in a spiral disk. (2) The bulge is offset by ~1.8kpc from a brightness minimum at the center of the optically bright inner disk. (3) A tidal stream, possibly associated with an ongoing satellite interaction, extends from the nucleated bulge along the disk. We interpret these properties as the results of one or more non-disruptive mergers between NGC 5523 and companion galaxies or satellites, raising the possibility that some galaxies become isolated because they have merged with former companions.
4405. NGC 628 H II regions
ID:
ivo://CDS.VizieR/J/AJ/120/1306
Title:
NGC 628 H II regions
Short Name:
J/AJ/120/1306
Date:
21 Oct 2021
Publisher:
CDS
Description:
Employing deep H{alpha} narrowband imagery, we identified and measured the fluxes of 137 small H II regions in the extreme outer disk (R>=R_25_) of the nearly face-on, Sc I galaxy NGC 628. A majority of these H II regions are located in two faint, outer spiral arms visible in H I maps. The faintest H II regions that could be measured have fluxes of only a few times 10^-16^ergs/cm^2^/s, which correspond to luminosities of 10^36^ergs/s, or a fraction of the Orion Nebula luminosity. The most distant object detected is at R~27kpc from the galaxy center. The massive star formation rate, as measured from the azimuthally averaged H{alpha} flux, is consistent with a monotonic decrease as far as R~1.3R_25_ (20kpc), where there is a sharp drop. The Schmidt law for the whole disk of NGC 628 corresponds to a relatively steep power law with n=2.9+/-0.2, but it "fails" below {Sigma}gas<=4M_{sun}_/pc^2^; the index depends strongly on the CO data used. We derived the luminosity function (LF) of 598 H II regions over the whole disk, and we compared the shapes of the cumulative LFs between R>=R_25_ and R<R_25_; the LF of the outer regions is significantly steeper than that of the inner regions.
4406. 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.
4407. NGC 346 HST VI photometry
ID:
ivo://CDS.VizieR/J/AJ/133/44
Title:
NGC 346 HST VI photometry
Short Name:
J/AJ/133/44
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the quest to understand how star formation occurs and propagates in the low-metallicity environment of the Small Magellanic Cloud (SMC), we acquired deep F555W (~V) and F814W (~I) Hubble Space Telescope ACS images of the young and massive star-forming region NGC 346. These images and their photometric analysis provide us with a snapshot of the star formation history of the region. We find evidence for star formation extending from ~10Gyr in the past until ~150Myr in the field of the SMC. The youngest stellar population (~3+/-1Myr) is associated with the NGC 346 cluster. It includes a rich component of low-mass pre-main-sequence stars mainly concentrated in a number of subclusters spatially colocated with CO clumps previously detected by Rubio and coworkers. Within our analysis uncertainties, these subclusters appear coeval with each other.
4408. NGC 6402. I. BV photometry
ID:
ivo://CDS.VizieR/J/AJ/146/57
Title:
NGC 6402. I. BV photometry
Short Name:
J/AJ/146/57
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present BV photometry of the Galactic globular cluster NGC 6402 (M14), based on 65 V frames and 67 B frames, reaching two magnitudes below the turnoff level. This represents, to the best of our knowledge, the deepest color-magnitude diagram (CMD) of NGC 6402 available in the literature. Statistical decontamination of field stars as well as differential reddening corrections are performed in order to derive a precise ridgeline and hence physical parameters of the cluster. We discuss previous attempts at deriving a reddening value for the cluster, and argue in favor of a value E(B-V)=0.57+/-0.02, which is significantly higher than indicated by either the Burstein & Heiles or Schlegel et al. (corrected according to Bonifacio et al.) interstellar dust maps. Differential reddening across the face of the cluster, which we find to be present at the level of {Delta}E(B-V){approx}0.17mag, is taken into account in our analysis. We measure several metallicity indicators based on the position of the red giant branch (RGB) in the cluster CMD. These give a metallicity of [Fe/H]=-1.38+/-0.07 on the Zinn & West scale and [Fe/H]=-1.28+/-0.08 on the new Carretta et al. (UVES) scale. We also provide measurements of other important photometric parameters for this cluster, including the position of the RGB luminosity function "bump" and the horizontal branch morphology. We compare the NGC 6402 ridgeline with that of NGC 5904 (M5) derived by Sandquist et al., and find evidence that NGC 6402 and M5 have approximately the same age to within the uncertainties, although the possibility that M14 may be slightly older cannot be ruled out.
4409. NGC 1960 IRAC and MIPS photometry
ID:
ivo://CDS.VizieR/J/MNRAS/420/2884
Title:
NGC 1960 IRAC and MIPS photometry
Short Name:
J/MNRAS/420/2884
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of Spitzer IRAC (3.6-8um) and MIPS (24um) imaging of members of the 16^+10^_-5_ Myr old open cluster NGC 1960 (M36). Models of terrestrial planet formation indicate that rocky planets are likely to achieve their final masses at around 10-30Myr, and thus this cluster is at an interesting epoch for planet formation. We find 21 B-F5 type stars and 14 F6-K9 type stars which have 24um excess emission, and thus determine that >30 per cent of B-F5 type stars and >23 per cent of F6-K9 type stars in this cluster have 24um excess emission. These excess frequencies are similar to those observed in other clusters of similar age. Three early-type stars have excesses at near-infrared wavelengths. Analysis of their spectral energy distributions confirms that these are true debris discs and not remnant primordial or transitional discs. None of the 61 Sun-like stars has confirmed near-infrared excess, and we can place a limit on the frequency of 8um excess emission around Sun-like stars of <7 per cent. All of the detected excesses are consistent with emission from debris discs and are not primordial.
4410. NGC 7538 IRS 1-3 and IRS 9 sources
ID:
ivo://CDS.VizieR/J/MNRAS/443/3218
Title:
NGC 7538 IRS 1-3 and IRS 9 sources
Short Name:
J/MNRAS/443/3218
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present deep and high-resolution (FWHM~0.4-arcsec) near-infrared (NIR) imaging observations of the NGC 7538 IRS 1-3 region (in JHK bands), and IRS 9 region (in HK bands) using the 8.2m Subaru telescope. The NIR analysis is complemented with Giant Metrewave Radio Telescope (GMRT) low-frequency observations at 325, 610, and 1280MHz, molecular line observations of H^13^CO^+^ (J=1-0), and archival Chandra X-ray observations. Using the 'J-H/H-K' diagram, 144 Class II and 24 Class I young stellar object (YSO) candidates are identified in the IRS 1-3 region. Further analysis using 'K/H-K' diagram yields 145 and 96 red sources in the IRS 1-3 and IRS 9 regions, respectively. A total of 27 sources are found to have X-ray counterparts. The YSO mass function (MF), constructed using a theoretical mass-luminosity relation, shows peaks at substellar (~0.08-0.18M_{sun}_) and intermediate (~1-1.78M_{sun}_) mass ranges for the IRS 1-3 region. The MF can be fitted by a power law in the low-mass regime with a slope of {Gamma} ~0.54-0.75, which is much shallower than the Salpeter value of 1.35. An upper limit of 10.2 is obtained for the star to brown dwarf ratio in the IRS 1-3 region. GMRT maps show a compact HII region associated with the IRS 1-3 sources, whose spectral index of 0.87+/-0.11 suggests optical thickness. This compact region is resolved into three separate peaks in higher resolution 1280MHz map, and the 'east' subpeak coincides with the IRS 2 source. H^13^CO^+^ (J=1-0) emission reveals peaks in both IRS 1-3 and IRS 9 regions, none of which are coincident with visible nebular emission, suggesting the presence of dense cloud nearby. The virial masses are approximately of the order of 1000 and 500M_{sun}_ for the clumps in IRS 1-3 and IRS 9 regions, respectively.