Browsing by Author "Barway, Sudhanshu"

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Bar fraction in lenticular galaxies: Dependence on luminosity and environment
(2010-10-15) Barway, Sudhanshu; Wadadekar, Yogesh; Kembhavi, A.K.
We present a study of bars in lenticular galaxies based on a sample of 371 galaxies from the SDSS-DR 7 and 2MASS in optical and near-infrared bands, respectively. We found a bar in 15% of the lenticular galaxies in our sample, which is consistent with recent stud- ies. The barred galaxy fraction shows a luminosity dependence, with faint lenticular galaxies (MK > −24.5, total absolute magnitude in K band) having a larger fraction of bars than bright lenticular galaxies (MK < −24.5). A similar trend is seen when Mr = −21.5, the total absolute magnitude in SDSS r band is used to divide the sample into faint and bright lenticular galaxies.We ﬁnd that faint galaxies in clusters show a higher bar fraction than their counterparts in the ﬁeld. This suggests that the formation of bars in lenticular galaxies not only depends on the total luminosity of galaxy but also on the environment of the host galaxy.
BVR photometry of a newly identified RS CVn binary star HD 61396
(2011-07-06) Barway, Sudhanshu; Pandey, S. K.
BVR photometry of a recently identiﬁed RS CVn binary star HD 61396, carried out during 2001, is presented. The new photometry reveal signiﬁcant evolution in the shape and amplitude of light curve when compared with those reported earlier by Padmakar et al.(2000). The traditional two-starspot model has been used to obtain the spot parameters from the observed light curve. Changes in the spot area and their location on the stellar surface are discernible from the extracted parameters from the new photometry.
HD 52452: New BVRI photometry
(2012-07-06) Barway, Sudhanshu; Pandey, S. K.
Lenticular Galaxy Formation - Possible Luminosity Dependence
(2007-03-27) Barway, Sudhanshu; Kembhavi, A.K.; Wadadekar, Yogesh; et al.
We investigate the correlation between the bulge eﬀective radius (re) and disk scale length (rd), in the near-infrared K band for lenticular galaxies in the ﬁeld and in clusters. We ﬁnd markedly diﬀerent relations between the two parameters as a function of luminosity. Lenticulars with total absolute magnitude fainter than MT = −24.5 show a positive correlation, in line with predictions of secular formation processes for the pseudo bulges of late-type disk galaxies. But brighter lenticulars with MT < −24.5 show an anti-correlation, indicating that they formed through a diﬀerent mechanism. The available data are insuﬃcient to reliably determine the eﬀect of galaxy environment on this correlation.
Luminosity dependent star-formation history of S0 galaxies: evidence from GALEX-SDSS-2MASS-WISE colours
(IUCAA, 2015-02) Barway, Sudhanshu; Wadadekar, Yogesh; Vaghmare, Kaustubh
Multicolor surface photometry of lenticulars galaxies I. The Data
(2011-07-06) Barway, Sudhanshu; Mayya, Y. D.; Kembhavi, A.K.; et al.
We present in this paper multicolor surface and aperture photometry in the B, V,R and K′ bands for a sample of 34 lenticular galaxies from the UGC catalogue. From surface photometric analysis, we obtain radial proﬁles of surface brightness, colors, ellipticity, position angle and the Fourier coeﬃcients which describe the departure of isophotal shapes from purely elliptical form and ﬁnd the presence of dust lanes, patches and ring like structure in several galaxies in the sample. We obtain total integrated magnitudes and colors and ﬁnd that these are in good agreement with the values from the RC3 catalogue. Isophotal colors are correlated with each other, following the sequence expected for early- type galaxies. The color gradients in lenticulars are more negative than the corresponding gradients in ellipticals. There is a good correlation between B − V and B − R color gradients, and the mean gradient in the B−V,B−R and V −K′ colors are −0.13±0.06, −0.18±0.06, −0.25±0.11 magnitude per dex in radius respectively.
Photometric Scaling Relations for Bulges of Galaxies
(2005-09-01) Ravikumar, C. D.; Kembhavi, A.K.; Barway, Sudhanshu; et al.
We study the photometric parameters of the bulges of galaxies of diﬀerent Hubble types including ellipticals, lenticulars, early and late type spirals and early type dwarf galaxies. Analyzing the distributions of various photometric parameters, and two and three-dimensional correlations between them, we ﬁnd that there is a diﬀerence in the correlations exhibited by bright (MK < −22) and faint bulges, irrespective of their Hubble type. Importantly, the bright bulges, which include typically E/S0 galaxies and bulges of early type spirals, are tightly distributed around a common photometric plane (PP), while their fainter counter parts, mainly bulges of late type spirals and dwarf galaxies show significant deviation from the planar distribution. We show that the speciﬁc entropy, determined from the bulge structural parameters, systematically increases as we move from late to early Hubble types. We interpret this as evidence for hierarchical merging and passive evolution scenarios for bright and faint bulges respectively.
A Sptzer Study Of Pseudobulges In so Galaxies - Secular Evoution of disk
(IUCAA, 2015-02) Vaghmare, Kaustubh; Barway, Sudhanshu; Kembhavi, A.K.
Super Massive Black Hole Fundamental Plane for Ellipticals
(2007-05-10) Barway, Sudhanshu; Kembhavi, A.K.
We obtain the coeﬃcients of a new fundamental plane for supermassive black holes at the centers of elliptical galaxies, involving measured central black hole mass and photometric parameters which deﬁne the light distribution. The galaxies are tightly distributed around this mass fundamental plane, with improvement in the rms residual over those obtained from the MBH − σ and MBH − L relations. This implies a strong multidimensional link between the central massive black hole formation and global photometric properties of elliptical galaxies and provides an improved estimate of black hole mass from galaxy data.
Unravelling the morphologies of Luminous Compact Galaxies using the HST/ACS GOODS survey
(2007-04-17) Rawat, A.; Kembhavi, A.K.; Barway, Sudhanshu; et al.
Context. Luminous Compact Galaxies (LCGs) (MB ≤ −20, R1/2 ≤ 4.5 kpc and EW0(OII) ≥15Å) constitute one of the most rapidly evolving galaxy populations over the last ∼8Gyr history of the universe. Due to their inherently compact sizes, any detailed quantitative analysis of their morphologies has proved to be diﬃcult in the past. Hence, the morphologies and thereby the local counterparts of these enigmatic sources have been hotly debated. Aims. Our aim is to use the high angular resolution, deep, multiband HST/ACS imaging data, from the HST/ACS GOODS survey, to study the quantitative morphology of a complete sample of LCGs in the redshift range 0.5 ≤ z ≤ 1.2. Methods. We have derived structural parameters for a representative sample of 39 LCGs selected from the GOODS-S HST/ACS ﬁeld, using full 2-dimensional surface brightness proﬁle ﬁtting of the galaxy images in each of the four ﬁlters available. B435W − z850LP color maps are constructed for the sample to aid in the morphological classiﬁcation. We then use the rest frame B band bulge ﬂux fraction (B/T) to determine the morphological class of galaxies which are well ﬁt by a ulge+disk two dimensional structure. Mergers were essentially identiﬁed visually by the presence of multiple maxima of comparable intensity in the rest frame B band images, aided by the color maps to distinguish them from HII regions. We also make use of the Spitzer 24 m source catalog of sources in the CDFS to derive the dust enshrouded star formation rates (SFR) for some of the sample LCGs Results. We derive the following morphological mix for our sample of intermediate redshift LCGs: Mergers: ∼36%, Disk dominated: ∼22%, S0: ∼20%, Early types: ∼7%, Irr/tadpole: ∼15%.We establish that our sample LCGs are intermediate mass objects with stellar mass ranging from 9.44 ≤ Log10(M/M⊙) ≤ 10.96, with a median mass of Log10(M/M⊙) = 10.32. We also derive SFR values ranging from a few to ∼ 65 M⊙/year as expected for this class of objects. We ﬁnd that LCGs account for ∼26% of the MB ≤ −20 galaxy population in the redshift range 0.5 ≤ z ≤ 1.2. We estimate a factor ∼11 fall in the comoving number density of blue LCGs from redshifts 0.5 ≤ z ≤ 1.2 to the current epoch, even though this number is subject to large uncertainities given the small sample size at zero redshift available from the literature. Conclusions. The strong redshift evolution exhibited by LCGs, and the fact that a signiﬁcant fraction of LCGs are in merging systems, seem to indicate that LCGs might be an important phase in the hierarchical evolution of galaxies. We envisage that some of the LCGs that are classiﬁed as merging systems, might go on to rebuild their disks and evolve into disk galaxies in the local universe.