- ID:
- ivo://CDS.VizieR/J/A+AS/142/347
- Title:
- BVRI photometry of NGC 6789
- Short Name:
- J/A+AS/142/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the results of a detailed B, V, R, I, and H{alpha} study of the isolated nearby blue compact dwarf (BCD) galaxy NGC 6789. The observed galaxy has not yet been resolved into stars up to now. On CCD frames obtained with 6m BTA telescope and 2.5m Nordic telescope the galaxy is well resolved. Its colour-magnitude diagram confirms the two component (core-halo) galaxy morphology, which consists of two stellar populations distinct in structure and colour: an inner high surface-brightness young population within 150pc from the center of the galaxy, and a relatively low surface-brightness intermediate-age population extending out to at least 600pc. The distance to the galaxy, estimated from the tip of the red giant branch (TRGB) is 2.1Mpc which places NGC 6789 close to the Local Group. From the mean colour of the RGB, the mean metal abundance of the halo population is estimated as [Fe/H]=~-1dex.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AZh/79/589
- Title:
- BVRI photometry of RC galaxies
- Short Name:
- J/AZh/79/589
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVRI data are presented for the majority of steep-spectrum objects in the RATAN-600 7.6cm catalog (RC) catalog with m(R)<23.5mag. Previously developed programs are applied to these data to estimate the redshifts and age of the stellar population of the host galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/119/777
- Title:
- BVRI photometry of Sagittarius dwarf irregular galaxy
- Short Name:
- J/AJ/119/777
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy SagDIG, obtained on the photometric night of 1994 October 8 (UT) using the University of Hawaii 2.2 m telescope at Mauna Kea.
- ID:
- ivo://CDS.VizieR/J/PASJ/55/1079
- Title:
- BVRi'z'JHKs photometry of ERO objects
- Short Name:
- J/PASJ/55/1079
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied the evolution of elliptical galaxies at z>~1 using a sample of 247 Extremely Red Objects (EROs) with R-Ks>3.35 (AB) and Ks<=22.1 (AB) constructed from BVRi'z'JHKs multicolor data of a 114arcmin^2^ area in the Subaru/XMM-Newton Deep Field taken with the Subaru Telescope and the UH 2.2m telescope. By fitting template spectra of old galaxies (OGs) and young, dusty starbursts (DSs) to the multicolor data, we classified EROs into these two classes and estimated their redshifts. We found that 58% of the EROs in our sample belong to the OG class and that these OGs have a wide range of colors at any redshift. We derived rest-frame B-band luminosity functions of OGs in our sample at z=1-1.5 and 1.5-2.5, and found that the number density of galaxies obeying passive evolution drops at z>~1.5 by a factor of three or more. The spatial correlation length of OGs is estimated to be r_0_>~8h^-1^Mpc, which is comparable to, or larger than, those of present-day early-type galaxies of similar luminosities. We also discussed properties of DSs in our data.
- ID:
- ivo://CDS.VizieR/J/ApJS/162/80
- Title:
- BVRJHKgr photometry of bright spiral galaxies
- Short Name:
- J/ApJS/162/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometrically calibrated images and surface photometry in the B, V, R, J, H, and K bands of 25, and in the g, r, and K bands of five nearby bright (B^0^_T_<12.5 mag) spiral galaxies with inclinations of 30{deg}-65{deg} spanning the Hubble sequence from Sa to Scd. Data are from The Ohio State University Bright Spiral Galaxy Survey (Eskridge et al., Cat. <J/ApJS/143/73>), the Two Micron All Sky Survey (2006AJ....131.1163S), and the Sloan Digital Sky Survey Second Data Release (Abazajian et al., 2004AJ....128..502A). Radial surface brightness profiles are extracted, and integrated magnitudes are measured from the profiles. Axis ratios, position angles, and scale lengths are measured from the near-infrared images. A one-dimensional bulge/disk decomposition is performed on the near-infrared images of galaxies with a nonnegligible bulge component, and an exponential disk is fit to the radial surface brightness profiles of the remaining galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/132/1593
- Title:
- BVR photometry of NGC 4594 globular clusters
- Short Name:
- J/AJ/132/1593
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed imaging analysis of the globular cluster (GC) system of the Sombrero galaxy (NGC 4594) has been accomplished using a six-image mosaic from the Hubble Space Telescope Advanced Camera for Surveys. The quality of the data is such that contamination by foreground stars and background galaxies is negligible for all but the faintest 5% of the GC luminosity function. This enables the study of an effectively pure sample of 659 GCs until ~2mag fainter than the turnover magnitude, which occurs at M^TOM^_V_=-7.60+/-0.06 for an assumed m-M=29.77. Two GC metallicity subpopulations are easily distinguishable, with the metal-poor subpopulation exhibiting a smaller intrinsic dispersion in color compared to the metal-rich subpopulation.
- ID:
- ivo://CDS.VizieR/J/AJ/110/212
- Title:
- BVR photometry of stars in NGC 2366
- Short Name:
- J/AJ/110/212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The stellar content of the Im galaxy NGC 2366 is discussed on the basis of CCD BVR photometry. The three brightest blue and red stars have been used to estimate its distance, obtaining a value of 2.9pc. The spatial distribution of the young stellar population is discussed in the light of the integrated color indices and the color-magnitude diagrams of different zones of the galaxy. A generalized star formation burst seems to have taken place about 50Myr ago. The youngest stars are preferentially formed in the South-West part of the bar, where the giant H II complex NGC 2363 is located, being younger and bluer. The bar seems to play a role favoring star formation in one of its extremes. Self-propagation however, does not seem to be triggering star formation at large scale. A small region, populated by very young stars has also been found at the East of the galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/752/42
- Title:
- BV time series in Ursa Major II
- Short Name:
- J/ApJ/752/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a B, V color-magnitude diagram (CMD) of the Milky Way dwarf satellite Ursa Major II (UMa II), spanning the magnitude range from V~15 to V~23.5mag and extending over an 18x18 arcmin^2^ area centered on the Galaxy. Our photometry goes down to about 2 mag below the Galaxy's main-sequence turnoff that we detected at V~21.5 mag. We have discovered a bona fide RR Lyrae variable star in UMa II, which we use to estimate a conservative dereddened distance modulus for the galaxy of (m-M)_0_=17.70+/-0.04+/-0.12mag, where the first error accounts for the uncertainties of the calibrated photometry, and the second reflects our lack of information on the metallicity of the star. The corresponding distance to UMa II is 34.7^+0.6^_-0.7_(^+2.0^_-1.9_)kpc. Our photometry shows evidence of a spread in the Galaxy's subgiant branch, compatible with a spread in metal abundance in the range between Z=0.0001 and Z=0.001. Based on our estimate of the distance, a comparison of the fiducial lines of the Galactic globular clusters M68 and M5 ([Fe/H]=-2.27+/-0.04 dex and -1.33+/-0.02 dex, respectively), with the position on the CMD of spectroscopically confirmed Galaxy members, may suggest the existence of stellar populations of different metal abundance/age in the central region of UMa II.
- ID:
- ivo://CDS.VizieR/J/PAZh/44/383
- Title:
- Byurakan-IRAS galaxies (BIG) with SDSS spectra
- Short Name:
- J/PAZh/44/383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The sample of Byurakan-IRAS galaxies (BIG) has been created based on optical identifications of IRAS Point Source Catalog (PSC) at high galactic latitudes. As a result, 1178 galaxies have been identified. 172 of them have been observed spectroscopically with Byurakan Astrophysical Observatory (BAO, Armenia) 2.6m, Special Astrophysical Observatory (SAO, Russia) 6m and Observatoire de Haute Provence (OHP, France) 1.93m telescopes. Later on, spectra were obtained for more 83 BIG objects in Sloan Digital Sky Survey (SDSS). We have extracted and studied these spectra, classified them and measured spectral features. Diagnostic diagrams have been built to distinguish starbursts (SB), LINERs and Seyfert galaxies. Cross-correlations were made for these objects with multiwavelength (MW) catalogues and their physical properties were studied. Among these 83 objects, 55 HII, 8 Seyfert galaxies, 2 LINERs, 4 other AGN, 6 composite spectrum objects, and 8 other emission-line galaxies have been revealed. Three of these objects are Ultra-Luminous InfraRed Galaxies (ULIRG).
- ID:
- ivo://CDS.VizieR/J/A+A/585/A47
- Title:
- CALIFA color/metallicity gradients connections
- Short Name:
- J/A+A/585/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study, for the first time in a statistically significant and well-defined sample, the relation between the outer-disk ionized-gas metallicity gradients and the presence of breaks in the surface brightness profiles of disk galaxies. Sloan Digital Sky Survey (SDSS) g'- and r'-band surface brightness, (g'-r') color, and ionized-gas oxygen abundance profiles for 324 galaxies within the Calar Alto Legacy Integral Field Area (CALIFA) survey are used for this purpose. We perform a detailed light-profile classification, finding that 84% of our disks show down- or up-bending profiles (Type II and Type III, respectively), while the remaining 16% are well fitted by one single exponential (Type I). The analysis of the color gradients at both sides of this break shows a U-shaped profile for most Type II galaxies with an average minimum (g'-r') color of ~0.5mag and an ionized-gas metallicity flattening associated with it only in the case of low-mass galaxies. Comparatively, more massive systems show a rather uniform negative metallicity gradient. The correlation between metallicity flattening and stellar mass for these systems results in p-values as low as 0.01. Independent of the mechanism having shaped the outer light profiles of these galaxies, stellar migration or a previous episode of star formation in a shrinking star-forming disk, it is clear that the imprint in their ionized-gas metallicity was different for low- and high-mass Type II galaxies. In the case of Type III disks, a positive correlation between the change in color and abundance gradient is found (the null hypothesis is ruled out with a p-value of 0.02), with the outer disks of Type III galaxies with masses <=10^10^M_{sun}_ showing a weak color reddening or even a bluing. This is interpreted as primarily due to a mass downsizing effect on the population of Type III galaxies that recently experienced an enhanced inside-out growth.