arXiv subjects

H. -J. Hagen

Publications and source records attributed to H. -J. Hagen.

41 records · Page 3Linked to original sources

arXiv2000

HS0907+1902: a new 4.2hr eclipsing dwarf nova

We report on follow-up spectroscopy and photometry of the cataclysmic variable candidate HS0907+1902 selected from the Hamburg Quasar Survey. B, V, and R photometry obtained during the first observed outburst of HS0907+1902 (V~13) reveals deep eclipses (DeltaV~2.1-2.8) and an orbital period Porb=4.2h with the eclipse depth decreasing to the red. The outburst eclipse profiles are symmetric, indicating an axisymmetrical brightness distribution in the accretion disc. We derive an inclination i~73deg-79deg from the eclipse duration. The quiescent spectrum obtained with the Hobby-Eberly Telescope shows double peaked emission lines of HI, HeI and FeI,II and clearly identifies the system as a dwarf nova. Absorption features of the secondary star are detected at red wavelengths from which a spectral class M3+-1.5 and a distance of d=320+-100pc are derived.

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arXiv2000

The Hamburg/SAO Survey for Emission-Line Galaxies. III. The Third List of 81 Galaxies

We present the third list with results {Tables 2 to 6 are available only in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html. Figures A1 to A9 will be made available only in the electronic version of the journal.} of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO - Special Astrophysical Observatory, Russia). This survey is based on the digitized objective-prism photoplate database of the Hamburg Quasar Survey (HQS). Here, we present new spectroscopic results of candidates which were obtained in 1998 with the 2.1 m KPNO and the 2.2 m Calar Alto telescopes. All candidates are selected in the declination band +35$^{\circ}$ to +40$^{\circ}$. The follow-up spectroscopy with the 2 m class telescopes confirmed 85 emission-line objects out of 113 observed candidates and allowed their quantitative spectral classification. For 80 of them, the redshifts are determined for the first time. For 5 previously known ELGs, line ratios are presented for the first time. We could classify 55 out of the 85 emission-line objects as BCG/H{\sc ii} galaxies or probable BCGs, 4 - as QSOs, 6 - as Seyfert galaxies, 1 - as super-association in a subluminous spiral galaxy, and 11 are low-excitation objects - either starburst nuclear (SBN), or dwarf amorphous nuclear starburst galaxies (DANS). We could not classify 8 ELGs. Further, for 8 more galaxies we did not detect any significant emission lines.

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arXiv1999

HS 1603+3820: a bright z(em)=2.51 quasar with a very rich heavy element absorption spectrum

During the course of Hamburg/CfA Bright Quasar Survey we discovered a bright (B=15.9), high redshift (z=2.51) quasar HS 1603+3820. The quasar has a rich complex of CIV absorbers, containing at least five systems, all within 3000 km/s from one another. Despite large ejection velocity (v(ej)>5000 km/s for all components) the complex is likely to be associated with the quasar. There are at least three more associated heavy element absorbers, two of which have z(abs)>z(em). Together, they make one of the richest known complexes of associated heavy element absorbers, and the richest in objects with B<16. The combination of redshift, brightness, richness of the metal absorption spectrum and richness of the associated absorption is unmatched among known quasars.

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arXiv1998

HS0551+7241: A New Possible Magnetic Cataclysmic Variable in the Hamburg/CfA Bright Quasar Survey

We present the analysis of the spectroscopic observations of a newly discovered cataclysmic variable HS0551+7241. In 1995 the star's brightness dropped by Delta(B)~2.5 mag and HS0551+7241 entered a low state lasting for ~2 yr. The H-alpha, H-beta and HeII(4686) emission line radial velocity curves show evidence of short ~50 min fluctuations superimposed on longer, ~4 hour variations. We found similar modulations in the line fluxes and the line equivalent widths. The continuum magnitude light curve suggest that HS0551+7241 may be an eclipsing system. If the 4 hour period is related to the orbital period then the mass function is ~0.138 M_sun. Relatively strong HeII(4686) emission and short fluctuation may suggest that the binary is an intermediate polar. In that case the ~50 min variations would correspond to the Alfven radius of ~3 x 10^10 cm.

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arXiv1996

SBS 0909+532: A New Double Gravitational Lens or Binary Quasar?

The z=1.377, B=17.0 mag quasar SBS 0909+532 A, B is a double with two images separated by 1.107 +/- 0.006 arcsec. Because the faint image has an emission line at the same wavelength as the MgII 2798 A emission line of the quasar, and lacks the broad MgIb absoption feature expected for a star with the same colors (a K star), we conclude that image B is a quasar with similar redshift to image A. The relative probabilities that the double is the smallest separation (4.8/h kpc for Ω_0=1) correlated quasar pair or a gravitational lens are \sim 1:10^6. If the object is a lens, the mean lens redshift is $ =0.5$ with 90% confidence bounds of 0.18 < z_l < 0.83 for Ω_0=1. If the lens is an elliptical galaxy, we expect it to be brighter than I < 19.5 mag. The broad band flux ratio varies with wavelength, with ΔI=0.31, ΔR=0.58, and ΔB=1.29 magnitudes, which is difficult to reconcile with the lensing hypothesis.

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