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381. BV phot. of a detached eclipsing binary in M 33
ID:
ivo://CDS.VizieR/J/ApJ/652/313
Title:
BV phot. of a detached eclipsing binary in M 33
Short Name:
J/ApJ/652/313
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first direct distance determination to a detached eclipsing binary in M33, which was found by the DIRECT Project. Located in the OB 66 association at coordinates (RA,DE)=(01:33:46.17,+30:44:39.9) for J2000.0, it was one of the most suitable detached eclipsing binaries found by DIRECT for distance determination, given its apparent magnitude and orbital period. We obtained follow-up BV time-series photometry, JHKs photometry, and optical spectroscopy from which we determined the parameters of the system. It contains two O7 main-sequence stars, with masses of 33.4+/-3.5 and 30.0+/-3.3M_{sun}_ and radii of 12.3+/-0.4 and 8.8+/-0.3R_{sun}_, respectively. We derive temperatures of 37000+/-1500 and 35600+/-1500K. Using BVRJHKs photometry for the flux calibration, we obtain a distance modulus of 24.92+/-0.12mag (964+/-54kpc), which is 0.3mag longer than the Key Project distance to M33. We discuss the implications of our result and the importance of establishing M33 as an independent rung on the cosmological distance ladder.
382. (BV) photometry in Carina dSph
ID:
ivo://CDS.VizieR/J/A+A/572/A10
Title:
(BV) photometry in Carina dSph
Short Name:
J/A+A/572/A10
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present deep photometry of the Carina dwarf Spheroidal galaxy in the B,V filters from CTIO/MOSAIC, out to and beyond the tidal radius of r_ell_~0.48{deg}. The accurately calibrated photometry is combined with spectroscopic metallicity distributions of Red Giant Branch stars to determine the detailed star formation and chemical evolution history of Carina. The star formation history confirms the episodic formation history of Carina and quantifies the duration and strength of each episode in great detail, as a function radius from the centre. Two main episodes of star formation occurred at old (>8Gyr) and intermediate (2-8Gyr) ages, both enriching stars starting from low metallicities ([Fe/H]<-2dex). By dividing the SFH into two components, we determine that 60+/-9 percent of the total number of stars formed within the intermediate age episode. Furthermore, within the tidal radius (0.48{deg} or 888pc) a total mass in stars of 1.07+/-0.08x10^6^M_{sun}_ was formed, giving Carina a stellar mass-to-light ratio of 1.8+/-0.8. Combining the detailed star formation history with spectroscopic observations of RGB stars, we are able to determine the detailed age-metallicity relation of each episode and the timescale of alpha-element evolution of Carina from individual stars. The oldest episode displays a tight age-metallicity relation during ~6Gyr with steadily declining alpha-element abundances and a possible alpha-element knee visible at [Fe/H]~-2.5dex. The intermediate age sequence displays a more complex age-metallicity relation starting from low metallicity and a sequence in alpha-element abundances with a slope much steeper than observed in the old episode, starting from [Fe/H]=-1.8dex and [Mg/Fe]~0.4dex and declining to Mg-poor values ([Mg/Fe]<-0.5dex). This indicates clearly that both episodes of star formation formed from gas with different abundance patterns , inconsistent with simple evolution in an isolated system.
383. BV photometry in Carina dwarf galaxy
ID:
ivo://CDS.VizieR/J/AJ/115/1840
Title:
BV photometry in Carina dwarf galaxy
Short Name:
J/AJ/115/1840
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have analyzed deep B and V photometry of the Carina dwarf spheroidal galaxy reaching below the old main-sequence turnoff to V~25. Using simulated color-magnitude diagrams to model a range of star formation scenarios, we have extracted a detailed, global star formation history. Carina experienced three significant episodes of star formation at ~15, 7, and 3Gyr. Contrary to the generic picture of galaxy evolution, however, the bulk of star formation, at least 50%, occurred during the episode 7Gyr ago, which may have lasted as long as 2Gyr. For unknown reasons, Carina formed only 10%-20% of its stars at an ancient epoch and then remained quiescent for more than 4 Gyr. The remainder (~30%) formed relatively recently, only 3Gyr ago. Interest in the local population of dwarf galaxies has increased lately because of their potential importance in the understanding of faint galaxy counts. We surmise that objects like Carina, which exhibits the most extreme episodic behavior of any of the dwarf spheroidal companions to the Galaxy, are capable of contributing to the observed excess of blue galaxies at B~24 only if the star formation occurred instantaneously.
384. BV photometry in Leo IV and Leo V dSphs
ID:
ivo://CDS.VizieR/J/ApJ/710/1664
Title:
BV photometry in Leo IV and Leo V dSphs
Short Name:
J/ApJ/710/1664
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained deep photometry in two 1{deg}x1{deg} fields covering the close pair of dwarf spheroidal galaxies Leo IV and Leo V and part of the area in between. From the distribution of likely red giant branch (RGB) and horizontal-branch (HB) stars in the data set, we find that both Leo IV and Leo V are significantly larger than indicated by previous measurements based on shallower data. With a half-light radius of r_h_=4.6'+/-0.8' (206+/-36pc) and r_h_=2.6'+/-0.6' (133+/-31pc), respectively, both systems are now well within the physical size bracket of typical dwarf spheroidal Milky Way satellites. Both are also found to be significantly elongated with an ellipticity of {epsilon}~0.5, a characteristic shared by many of the fainter (M_V_>-8) Milky Way dwarf spheroidals. The large spatial extent of our survey allows us to search for extra-tidal features in the area between the two dwarf galaxies with unprecedented sensitivity. The spatial distribution of candidate RGB and HB stars in this region is found to be non-uniform at the ~3{sigma} level. We investigate different scenarios to explain the close proximity of Leo IV and Leo V, and the possible tidal bridge between them.
385. BV photometry of dwarf Cepheids in Carina
ID:
ivo://CDS.VizieR/J/AJ/146/141
Title:
BV photometry of dwarf Cepheids in Carina
Short Name:
J/AJ/146/141
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the detection of 388 pulsating variable stars (and some additional miscellaneous variables) in the Carina dwarf spheroidal galaxy over an area covering the full visible extent of the galaxy and extending a few times beyond its photometric (King) tidal radius along the direction of its major axis. Included in this total are 340 newly discovered dwarf Cepheids (DCs), which are mostly located ~2.5mag below the horizontal branch and have very short periods (<0.1days), typical of their class and consistent with their location on the upper part of the extended main sequence of the younger populations of the galaxy. Several extra-tidal DCs were found in our survey up to a distance of ~1{deg} from the center of Carina. Our sample also includes RR Lyrae stars and anomalous Cepheids, some of which were found outside the galaxy's tidal radius as well. This supports past works that suggest that Carina is undergoing tidal disruption. We use the period-luminosity relationship for DCs to estimate a distance modulus of {mu}_0_=20.17+/-0.10mag, in very good agreement with the estimate from RR Lyrae stars. We find some important differences in the properties of the DCs of Carina and those in Fornax and the LMC, the only extragalactic samples of DCs currently known. These differences may reflect a metallicity spread, depth along the line of sight, and/or different evolutionary paths of the DC stars.
386. BV photometry of galactic nuclei
ID:
ivo://CDS.VizieR/J/AZh/71/706
Title:
BV photometry of galactic nuclei
Short Name:
J/AZh/71/706
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using all data in the literature on multiaperture photometry in B and V bands for 237 galaxies, a list of candidates for galaxies with chemically distinct nuclei is compiled. Twenty-five to 50 percent of galaxies with morphological types from E to Sb are found to be such candidates.
387. BV photometry of irregular galaxies
ID:
ivo://CDS.VizieR/J/A+AS/128/459
Title:
BV photometry of irregular galaxies
Short Name:
J/A+AS/128/459
Date:
21 Oct 2021
Publisher:
CDS
Description:
The tables shows the photometry and colour index for the observed galaxy, with the image parameter SHAR. This parameter is a measure of the difference between the observed width of the object and the psf model.
388. BVRcIc photometry of NGC 821 globular clusters
ID:
ivo://CDS.VizieR/J/MNRAS/385/361
Title:
BVRcIc photometry of NGC 821 globular clusters
Short Name:
J/MNRAS/385/361
Date:
21 Oct 2021
Publisher:
CDS
Description:
We performed a photometric study of globular clusters around the isolated elliptical galaxy NGC 821. B, V and R-band photometry come from the Mini-Mosaic imager on the 3.5-m Wisconsin Indiana Yale NOAO (WIYN) telescope. Observations were conducted between November 30 - December 2, 2005. Average seeing conditions were ~0.7". Two Hubble Space Telescope (HST) Wide-Field Planetary Camera 2 (WFPC2) fields were analysed in the V and I-bands. Objects in this catalogue are the globular cluster candidates according to the selection criteria detailed in the journal article. Astrometric solution is from USNO-B stars. Note the center of NGC 821 on this system is located at 02:08:21.118 +10:59:42.21. Photometry has been corrected for Galactic extinction and we used a distance modulus of m-M=31.75 in our analysis.
389. BV(RI)c bands of Cepheids in IC 1613
ID:
ivo://CDS.VizieR/J/A+A/445/901
Title:
BV(RI)c bands of Cepheids in IC 1613
Short Name:
J/A+A/445/901
Date:
21 Oct 2021
Publisher:
CDS
Description:
A set of six BV(RI)c observations collected with the WFI at the ESO 2.2m telescope have been used to derive multicolor data of Cepheids in IC 1613 identified in previous surveys. Since part of the previously known data were obtained only in V,I filters or without filter (Wh) bands, the method of Freedman has been applied to get reliable mean intensity values of Cepheid magnitudes in the various bands. The resulting slopes of the relations in the BVI bands are similar, within the uncertainties, to those previously obtained by other authors for the LMC. The distribution of the Cepheids in the period-color diagrams is compatible with a change near P about 10d as observed in LMC. The distribution in the color-color diagrams is more similar to that in SMC, and this should be related to the very low metallicity of the galaxy.
390. BVRI imaging of M 51-type pairs
ID:
ivo://CDS.VizieR/J/A+AS/141/103
Title:
BVRI imaging of M 51-type pairs
Short Name:
J/A+AS/141/103
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present decompositions of azimuthally averaged surface brightness profiles in optical B, V, R and I-bands for a sample of 40 M 51-type interacting galaxies. The profiles were modelled by an exponential disk and a spherical bulge described either by the R^1/4^ law or by an exponential function. Half of the galaxies were well fitted by both bulge models, whereas for 35% the exponential function was a better choice. Special care was taken on eliminating superpositions of the companion galaxies. The mean B-band central surface brightness {mu}_0_was found to be 21.5mag/arcsec^2^, which is near to the value originally found by Freeman (1970ApJ...160..811F), but the scatter was fairly large. Galaxy interactions have strongly modified the disks in many of the galaxies in the sample. For example, six of them had extremely flat brightness profiles outside the exponential part of the disk, and many showed significant isophotal twists.