The Hamburg Quasar Survey

Hagen, H. J.; Engels, D.; Groote, D.; Reimers, D.

doi:10.1007/978-94-011-1146-1_153

Cited by 145 publications

(179 citation statements)

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“…9 it can be seen that it is very unlikely that a SN is detected more than 10 days after optical maximum. The largest observed difference is SN1997ab with t max − t disc = −323 days (Hagen et al 1997).…”

Section: Statistical Studies With the Uscmentioning

confidence: 96%

A unified supernova catalogue

Lennarz

Altmann

Wiebusch

2012

A&A

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In this paper a new supernova catalogue containing data for 5526 extragalactic supernovae that were discovered up to 2010 December 31 is presented. It combines several catalogues that are currently available online in a consistent and traceable way. During the comparison of the catalogues inconsistent entries were identified and resolved where possible. Remaining inconsistencies are marked transparently and can be easily identified. Thus it is possible to select a high-quality sample in a most simple way. Where available, redshift-based distance estimates to the supernovae were replaced by journal-refereed distances. Examples of statistical studies that are now possible with this new catalogue are presented in this paper.

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Section: Statistical Studies With the Uscmentioning

confidence: 96%

A unified supernova catalogue

Lennarz

Altmann

Wiebusch

2012

A&A

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“…The Hamburg Quasar Survey (HQS) was carried out, starting in 1980, with the 80 cm Schmidt telescope at the GermanSpanish Astronomical Center (DSAZ) on Calar Alto, Spain (Hagen et al 1995). Although it was primarily initiated as a quasar survey, it is also a very rich source of faint blue stars.…”

Section: Introductionmentioning

confidence: 99%

“…A search software selects quasar candidates as well as faint blue stars from the 30 000-50 000 spectra per plate in the magnitude range of 13. m 5 ≤ B ≤ 18. m 5. Selection criteria are blue continua and/or emission lines (Hagen et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Spectral analysis of sdB stars from the Hamburg Quasar Survey

Edelmann¹,

Heber²,

Hagen

et al. 2003

A&A

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Abstract. We present the results of a spectral analysis of a large sample of subdwarf B stars selected from follow-up observations of candidates from the Hamburg Quasar Survey. Fundamental parameters (effective temperature, gravity, and helium abundance) were determined by matching synthetic line profiles calculated from model atmospheres to all hydrogen and helium absorption lines present in the observed optical spectra. The derived helium abundances are compared with the atmospheric parameters to search for possible trends. We discovered a correlation between the helium abundance and the effective temperature: the larger the temperature, the larger the photospheric helium content of sdB stars. Additionally, a separation into two sequences of sdB stars in the effective temperature -helium abundance plane is detected. We compared our analysis results with data from the literature. The stars from our sample are found to be somewhat more luminous. This can only partly be explained by NLTE effects. Three apparently normal B stars were discovered, which could be massive stars far away from the galactic plane (7-19 kpc). Radial velocities were measured for 23 stars from which we discovered a new radial velocity variable sdB star.

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“…We are selecting CV candidates from the Hamburg Quasar Survey (HQS, Hagen et al 1995), an objective prism Schmidt survey of the northern hemisphere covering 13 600 deg 2 at high galactic latitudes with a limiting magnitude 17.5 < ∼ B < ∼ 18.5. The survey resulted in 50 new CVs, including a number of peculiar objects (e.g.…”

Section: Introductionmentioning

confidence: 99%

Dwarf novae in the Hamburg quasar survey: rarer than expected

Aungwerojwit¹,

Gänsicke²,

Rodríguez‐Gil

et al. 2006

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Aims. We report the discovery of five new dwarf novae that were spectroscopically identified in the Hamburg Quasar Survey (HQS), and discuss the properties of the sample of new dwarf novae from the HQS. Methods. Follow-up time-resolved spectroscopy and photometry have been obtained to characterise the new systems. Results. The orbital periods determined from analyses of the radial velocity variations and/or orbital photometric variability are P orb 105.1 min or P orb 109.9 min for HS 0417+7445, P orb = 114.3 ± 2.7 min for HS 1016+3412, P orb = 92.66 ± 0.17 min for HS 1340+1524, P orb = 272.317 ± 0.001 min for HS 1857+7127, and P orb = 258.02 ± 0.56 min for HS 2214+2845. HS 1857+7127 is found to be partially eclipsing. In HS 2214+2845 the secondary star of spectral type M3 ± 1 is clearly detected, and we estimate the distance to the system to be d = 390 ± 40 pc. We recorded one superoutburst of HS 0417+7445, identifying the system as a SU UMatype dwarf nova. HS 1016+3412 and HS 1340+1524 have rare outbursts, and their subtype is yet undetermined. HS 1857+7127 frequently varies in brightness and may be a Z Cam-type dwarf nova. HS 2214+2845 is a U Gem-type dwarf nova with a most likely cycle length of 71 d. Conclusions. To date, 14 new dwarf novae have been identified in the HQS. The ratio of short-period (<3 h) to long-period (>3 h) systems of this sample is 1.3, much smaller compared to the ratio of 2.7 found for all known dwarf novae. The HQS dwarf novae display typically infrequent or low-amplitude outburst activity, underlining the strength of spectroscopic selection in identifying new CVs independently of their variability. The spectroscopic properties of short-period CVs in the HQS, newly identified and previously known, suggest that most, or possibly all of them are still evolving towards the minimum period. Their total number agrees with the predictions of population models within an order of magnitude. However, the bulk of all CVs is predicted to have evolved past the minimum period, and those systems remain unidentified. This suggests that those post-bounce systems have markedly weaker Hβ emission lines compared to the average known short-period CVs, and undergo no or extremely rare outbursts.

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The Hamburg Quasar Survey

Cited by 145 publications

References 0 publications

A unified supernova catalogue

A unified supernova catalogue

Spectral analysis of sdB stars from the Hamburg Quasar Survey

Dwarf novae in the Hamburg quasar survey: rarer than expected

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