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2791. Photometry of 119 HII regions in M33
ID:
ivo://CDS.VizieR/J/A+A/595/A43
Title:
Photometry of 119 HII regions in M33
Short Name:
J/A+A/595/A43
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the dust properties of a sample of HII regions in the Local Group Galaxy M 33 presenting different spatial configurations between stars, gas, and dust. We obtain the spectral energy distribution (SED) from the UV (GALEX) to the far IR (Herschel) performing photometry in each HII region of the sample. We model the SED using DustEM tool to understand the dust evolution in different environments. The fraction of very small grains can be affected by the conditions of the interstellar environment: strong shocks existing in the interior of the most luminous HII regions can lead to fragmentation of big grains into smaller ones, while the more evolved objects provide a more quiescent environment where reformation of dust big grains might occur.
2792. Photometry of LBGs, LAEs and GNBs at z~2.85
ID:
ivo://CDS.VizieR/J/ApJ/779/65
Title:
Photometry of LBGs, LAEs and GNBs at z~2.85
Short Name:
J/ApJ/779/65
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a survey for z~2.85 Lyman-continuum (LyC) emission in the HS1549+1933 field and place constraints on the amount of ionizing radiation escaping from star-forming galaxies. Using a custom narrowband filter (NB3420) tuned to wavelengths just below the Lyman limit at z>=2.82, we probe the LyC spectral region of 49 Lyman break galaxies (LBGs) and 91 Ly{alpha} emitters (LAEs) spectroscopically confirmed at z>=2.82. Four LBGs and seven LAEs are detected in NB3420. Using V-band data probing the rest-frame nonionizing UV, we observe that many NB3420-detected galaxies exhibit spatial offsets between their LyC and nonionizing UV emission and are characterized by extremely blue NB3420-V colors, corresponding to low ratios of nonionizing to ionizing radiation (F_UV_/F_LyC_) that are in tension with current stellar population synthesis models. We measure average values of (F_UV_/F_LyC_) for our LBG and LAE samples, correcting for foreground galaxy contamination and H I absorption in the intergalactic medium. We find (F_UV_/F_LyC_)_corr_^LBG^=82+/-45 and (F_UV_/F_LyC_)_corr_^LAE^=7.4+/-3.6. These flux density ratios correspond, respectively, to relative LyC escape fractions of f_esc,rel_^LBG^=5%-8%, and f_esc,rel_^LAE^=18%-49% absolute LyC escape fractions of f_esc,rel_^LBG^=1%-2% and f_esc,rel_^LAE^=5%-15%, and a comoving LyC emissivity from star-forming galaxies of 8.8-15.0x10^24^ erg/s/Hz/Mpc^3^. In order to study the differential properties of galaxies with and without LyC detections, we analyze narrowband Ly{alpha} imaging and rest-frame near-infrared imaging, finding that while LAEs with LyC detections have lower Ly{alpha} equivalent widths on average, there is no substantial difference in the rest-frame near-infrared colors of LBGs or LAEs with and without LyC detections. These preliminary results are consistent with an orientation-dependent model where LyC emission escapes through cleared paths in a patchy interstellar medium.
2793. Photometry of nearby cluster galaxies
ID:
ivo://CDS.VizieR/J/ApJS/153/397
Title:
Photometry of nearby cluster galaxies
Short Name:
J/ApJS/153/397
Date:
21 Oct 2021
Publisher:
CDS
Description:
Photometric observations are presented for 8747 galaxies in the fields of 28 clusters with redshifts in the range 0.05<z<0.11 and spanning a wide range in Abell richness class. The primary motivation for this study is to provide a nearby sample of clusters whose galaxy populations can be used to provide an anchor point for evolutionary studies of cluster galaxy populations.
2794. Photometry of NGC 3109 carbon stars
ID:
ivo://CDS.VizieR/J/A+A/410/795
Title:
Photometry of NGC 3109 carbon stars
Short Name:
J/A+A/410/795
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a CFH12K wide field survey of the carbon star population in and around NGC 3109. Carbon stars, the brightest members of the intermediate-age population, were found nearly exclusively in and near the disk of NGC 3109, ruling out the existence of an extensive intermediate-age halo like the one found in NGC 6822. Over 400 carbon stars identified have M_I_=-4.71, confirming the nearly universality of mean magnitude of C star populations in Local Group galaxies. Star counts over the field reveal that NGC 3109 is a truncated disk shaped galaxy without an extensive stellar halo. The minor axis star counts reach the foreground density between 4' and 5', a distance that can be explained by an inclined disk rather than a spheroidal halo. We calculate a global C/M ratio of 1.75+/-0.20, a value expected for such a metal poor galaxy.
2795. Photometry of S5 0716+714
ID:
ivo://CDS.VizieR/J/AJ/129/1818
Title:
Photometry of S5 0716+714
Short Name:
J/AJ/129/1818
Date:
21 Oct 2021
Publisher:
CDS
Description:
Optical monitoring of S5 0716+714 was performed with a 60/90 Schmidt telescope in 2003 November and December and 2004 January for studying the variability of the object on short timescales. Because of the high brightness of the source, we could carry out quasi-simultaneous measurements in three bands with a temporal resolution of about 20min by using one single telescope.
2796. Photometry of star clusters in 5 nearby gal.
ID:
ivo://CDS.VizieR/J/A+A/529/A25
Title:
Photometry of star clusters in 5 nearby gal.
Short Name:
J/A+A/529/A25
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recent studies have started to cast doubt on the assumption that most stars are formed in clusters. Observational studies of field stars and star cluster systems in nearby galaxies can lead to better constraints on the fraction of stars forming in clusters. Ultimately this may lead to a better understanding of star formation in galaxies, and galaxy evolution in general. We aim to constrain the amount of star formation happening in long-lived clusters for four galaxies through the homogeneous, simultaneous study of field stars and star clusters.
2797. Photometry of star clusters in NGC 1380
ID:
ivo://CDS.VizieR/J/A+A/467/1003
Title:
Photometry of star clusters in NGC 1380
Short Name:
J/A+A/467/1003
Date:
21 Oct 2021
Publisher:
CDS
Description:
NGC 1380 is a lenticular galaxy located near the center of the Fornax Cluster, northeast of NGC 1399. The globular cluster system of this galaxy was previously studied only from the ground. Recent studies of similar early-type galaxies, specially lenticular ones, reveal the existence of star clusters that apparently break up the traditional open/globular cluster dichotomy. With higher quality photometry from HST/WFPC2 we study the star clusters in NGC 1380, measuring their magnitudes, colours, sizes and projected distances from the center of the galaxy. We used deep archival HST/WFPC2 in the B and V bands. We built colour magnitude diagrams from which we selected a sample of cluster candidates. We also analysed their colour distribution and measured their sizes. Based on their location in the luminosity-size diagram we estimated probabilities of them being typical globular clusters as those found in the Galaxy. A total of about 570 cluster candidates were found down to V=26.5. We measured sizes for approximately 200 of them. The observed colour distribution has three apparent peaks. Likewise for the size distribution. We identified the smaller population as being mainly typical globular clusters, while the more extended objects have small probabilities of being such objects. Different correlations between absolute magnitudes, sizes, colours and location were inferred for these cluster sub-populations. Most extended clusters (Reff>4pc) share similar properties to the diffuse star clusters reported to inhabit luminous early-type galaxies in the Virgo galaxy cluster such as being of low surface brightness and fainter than MV~-8. We also report on a small group of (R_eff_~10pc), -8<MV<-6, red clusters located near the centre of NGC 1380, which may be interpreted as faint fuzzies.
2798. Photometry of stars in the LeoA HST WFC3 field
ID:
ivo://CDS.VizieR/J/A+A/614/A144
Title:
Photometry of stars in the LeoA HST WFC3 field
Short Name:
J/A+A/614/A144
Date:
21 Oct 2021
Publisher:
CDS
Description:
LeoA is an isolated gas-rich dwarf irregular galaxy of low stellar mass and metallicity residing at the outskirts of the Local Group. Ages of the stellar populations in LeoA range from ~10Myr to ~10Gyr. A large stellar halo (up to the deprojected distance of ~1.7kpc was discovered based on Subaru wide-field photometry of red giant branch stars. We analysed HST WFC3 archive observation data in the field that is partly located beyond the previously known limits of the LeoA galaxy. We performed photometry of star-like objects in the F475W and F814W passbands and studied the spatial distribution of the Leo A stars below the horizontal branch. We report a discovery of stellar halo populations (subgiants and faint red giants) in the Leo A galaxy extending up to ~2.3kpc deprojected distance from the galaxy centre. Analysis of the colour-magnitude diagram suggests old (>5Gyr) stellar populations of very low metallicity (Z~0.0001).
2799. Photometry of the Hercules dwarf galaxy
ID:
ivo://CDS.VizieR/J/ApJ/704/898
Title:
Photometry of the Hercules dwarf galaxy
Short Name:
J/ApJ/704/898
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present imaging of the recently discovered Hercules Milky Way satellite and its surrounding regions to study its structure, star formation history and to thoroughly search for signs of disruption. We robustly determine the distance, luminosity, size, and morphology of Hercules utilizing a bootstrap approach to characterize our uncertainties. We derive a distance to Hercules via a comparison to empirical and theoretical isochrones, finding a best match with the isochrone of M92, which yields a distance of 133+/-6kpc. As previous studies have found, Hercules is very elongated, with {epsilon}=0.67+/-0.03 and a half-light radius of r_h_~230pc. Using the color-magnitude-fitting package StarFISH, we determine that Hercules is old (>12Gyr) and metal-poor ([Fe/H]~-2.0), with a spread in metallicity, in agreement with previous spectroscopic work. This result is robust with respect to slight variations in the distance to Hercules and mismatches between the observed Hercules color-magnitude diagram and theoretical isochrones. We infer a total absolute magnitude of M_V_=-6.2+/-0.4. Our innovative search for external Hercules structure both in the plane of the sky and along the line of sight yields some evidence that Hercules is embedded in a larger stream of stars. A clear stellar extension is seen to the northwest with several additional candidate stellar overdensities along the position angle of Hercules out to ~35' (~1.3kpc).
2800. Photometry of the Tuc dwarf galaxy
ID:
ivo://CDS.VizieR/J/A+A/315/40
Title:
Photometry of the Tuc dwarf galaxy
Short Name:
J/A+A/315/40
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present V and I CCD photometry for ~360 stars in the recently discovered dwarf galaxy Tucana. The large field investigated and the accurate photometric calibration make our data complementary to the deeper HST photometry. From the I magnitude of the tip of the red giant branch we estimate a distance modulus (m-M)_0_=24.69+/-0.16, corresponding to 870+/-60Kpc, confirming that Tucana is an isolated dwarf spheroidal located almost at the border of the Local Group. From the color of the red giant branch tip and by direct comparison with the giant branches of galactic globular clusters we estimate a metallicity [Fe/H]=-1.8+/-0.2, with no clear indication for a metallicity spread. The color-magnitude diagram indicates that Tucana has had a single star formation burst at the epoch of the Galactic globular cluster star formation. There is no evidence for an intermediate or young stellar population. We derive the V luminosity profile, the surface density profile of resolved stars, and the structural parameters of Tucana, from which we confirm that Tucana participates to the general metallicity-surface brightness-absolute magnitude relations defined by the Galaxy and M31 dwarf spheroidal and dwarf elliptical companions.