189 research outputs found

    Spectroscopy of Stellar-Like Objects Contained in the Second Byurakan Survey. I

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    The results of spectroscopic observations of 363 star-like objects from the Second Byurakan Survey (SBS) are reported. This SBS's subsample has proven to be a rich source of newly identified quasars, Seyfert type galaxies, degenerate stars and hot subdwarfs. In the subsample here studied, we identified 35 new QSOs, 142 White Dwarfs (WDs) the majority of which, 114 are of DA type, 55 subdwarfs (29 of which are sdB-type stars), 10 HBB, 16 NHB, 54 G-type and 25 F-type stars, two objects with composite spectra, four Cataclismic Variables (CV), two peculiar emission line stars, 17 objects with continuous spectra, as well as one planetary nebula. Among the 35 QSOs we have found two Broad Absorption Line (BAL) QSOs, namely SBS 1423+500 and SBS 1435+500A. Magnitudes, redshifts, and slit spectra for all QSOs, also some typical spectra of the peculiar stars are presented. We estimate the minimum surface density of bright QSOs in redshift range 0.3<z<2.2 to be 0.05 per sq. deg. for B<17.0 and 0.10 per sq. deg. for B<17.5.Comment: 22 pages, 3 tables, 4 figures, PASP in pres

    Spectral Observations of Faint Markarian Galaxies of the Second Byurakan Survey. II

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    We continue the program of spectroscopic observations of objects from the Second Byurakan Survey (SBS). This survey contains more than 1300 galaxies and 1700 star-like objects with m(pg)<19.5. Our work is aimed towards the construction of a complete sample of faint Markarian galaxies. Here, we present spectroscopic data for 43 galaxies. Amongst them six new Seyfert galaxies are found, namely two Sy 1 type (SBS 1343+544 and SBS 1433+500), one Sy 2 type (SBS 1620+545) and three likely Sy 2 type galaxies (SBS 1205+556, SBS 1344+527, SBS 1436+597). SBS 1343+544 falls into the luminosity gap between low-redshift QSOs and high luminosity Sefert galaxies. In the sample studied here, another 36 emission-line galaxies were spectroscopically confirmed. Thus far, 102 SBS galaxies brighter than m(pg)=17.5 have been observed with the Cananea 2.1m GHO telescope. The apparent magnitude and redshift distributions, the spectral classification, the relative intensities of emission lines, and other parameters, as well as slit spectra for all 43 observed galaxies are presented.Comment: 7 pages, 7 figures, 2 tables, Latex, aaspp4.sty and aj_pt.sty, Submitted to Astronomical Journa

    Multiband Comparative Study of Optical Microvariability in RL vs. RQ Quasars

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    We present the results of an optical multi-band (BVR) photometric monitoring program of 22 core-dominated radio-loud quasars (CRLQs) and 22 radio-quiet quasars (RQQs). The aim was to compare the properties of microvariability in both types of quasars. We detected optical microvariability in 5 RQQs and 4 CRLQs. Our results confirm that microvariability in RQQs may be as frequent as in CRLQs. In addition we compare microvariability duty cycles in different bands. Finally, the implications for the origin of the microvariations are briefly discussed.Comment: 17 pages, 14 figures, Accepted for publication in the Astronomical Journa

    The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability

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    We report the discovery of rapid variations of a high-velocity CIV broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4sigma) variability in the equivalent width of the broad (~4000 km/s wide) CIV trough on rest-frame timescales as short as 1.20 days (~29 hours), the shortest broad absorption line variability timescale yet reported. The equivalent width varied by ~10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of n_e > 3.9 x 10^5 cm^-3. The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios.Comment: 15 pages, 14 figures. Accepted for publication in the Astrophysical Journa

    The Second Byurakan Survey Galaxies. I. The Optical Database

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    A database for the entire catalog of the Second Byurakan Survey (SBS) galaxies is presented. It contains new measurements of their optical parameters and additional information taken from the literature and other databases. The measurements were made using Ipg(near-infrared), Fpg(red) and Jpg(blue) band images from photographic sky survey plates obtained by the Palomar Schmidt telescope and extracted from the STScI Digital Sky Survey (DSS). The database provides accurate coordinates, morphological type, spectral and activity classes, apparent magnitudes and diameters, axial ratios, and position angles, as well as number counts of neighboring objects in a circle of radius 50 kpc. The total number of individual SBS objects in the database is now 1676. The 188 Markarian galaxies which were re-discovered by SBS are not included in this database. We also include redshifts that are now available for 1576 SBS objects, as well as 2MASS infrared magnitudes for 1117 SBS galaxies.Comment: 13 pages, 1 figure, 1 tabl

    Galaxies in front of Quasars: Mrk 1456 and SDSS J114719.90+522923.2

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    The chance projection of the disk of Mrk~1456 onto a background QSO is similar to the case of SBS 1543+593/HS 1543+5921. Mrk~1456 is a luminous, late-type spiral at z ~ 0.05. Though the QSO, SDSS J114719.90+522923.2 at z ~ 2, has not yet been observed with ultraviolet spectroscopy, it shows strong Ca II absorption at the redshift of Mrk 1456 which gives evidence that it is a possible Damped Lyman Alpha absorber. Spectroscopy of the star-forming nucleus of Mrk~1456 allows us to apply emission-line diagnostics to infer the chemical abundances at the center of the galaxy, and to make a prediction of the expected metallicity on the sightline to the QSO.Comment: 23 pages, 4 figures, accepted for publication in A
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