109 citations · 297 across the 16 of their papers we have counts for
16 papers
Constraining the Metallicities of Damped Ly Systems Using Extinction Curves
Hassan Fathivavsari
In this paper, we present a new method to constrain the metallicities of high redshift damped Ly (DLA) absorbers using observed extinction curves. This is the first time such an…
Using Machine Learning to Find Ghostly Damped Ly Systems in SDSS DR14
Hassan Fathivavsari
We report the discovery of 59 new ghostly absorbers from the Sloan Digital Sky Survey (SDSS) Data Release 14 (DR14). These absorbers, with , reveal…
Deep Learning Prediction of Quasars Broad Ly Emission Line
Hassan Fathivavsari
We have employed deep neural network, or deep learning to predict the flux and the shape of the broad Ly emission lines in the spectra of quasars. We use 17870 high signal-to-no…
Deep Hubble Space Telescope Imaging on the Extended Ly Emission of a QSO at with Damped Lyman Alpha System as a Natural Coronagraph
Jiani Ding, Zheng Cai, J. Xavier Prochaska +5
Recent observations suggest that proximate damped Ly (PDLA) systems can be used to study the host galaxies of Quasi-stellar objects (QSOs), because the PDLAs can block the brigh…
Ghostly Damped Ly Systems: Tracers of Gas Flows in the Close Vicinity of Quasars ?
Hassan Fathivavsari
We have searched the Sloan Digital Sky Survey Data Release 12 for ghostly Damped Ly (DLA) systems. These systems, located at the redshift of the quasars, show strong absorption…
Proximate Molecular Quasar Absorbers: Excess of damped H2 systems at zabs~zQSO in SDSS DR14
P. Noterdaeme, S. Balashev, J. -K. Krogager +4
We present results from a search for strong H2 absorption systems proximate to quasars (zabs~zem) in the Sloan Digital Sky Survey (SDSS) Data Release 14. The search is based on the…
Constraining the gap size in the disk around HD 100546 in the mid-infrared
Narges Jamialahmadi, Thorsten Ratzka, Olja Panic +6
We refine the gap size measurements of the disk surrounding the Herbig Ae star HD 100546 in the N band. Our new mid-infrared interferometric (MIDI) data have been taken with the UT…
Eclipsing damped Ly systems in the Sloan Digital Sky Survey Data Release 12
Hassan Fathivavsari, Patrick Petitjean, Narges Jamialahmadi +6
We present the results of our automatic search for proximate damped Ly absorption (PDLA) systems in the quasar spectra from the Sloan Digital Sky Survey Data Release 12. We cons…
Near Infrared spectroscopic observations of high redshift C~{\sc i} absorbers
Siwei Zou, Patrick Petitjean, Pasquier Noterdaeme +5
We study a sample of 17 z>1.5 absorbers selected based on the presence of strong CI absorption lines in SDSS spectra and observed with the ESO-VLT spectrograph X-shooter. We derive…
On the inner disk structure of MWC480: evidence for asymmetries?
Narges Jamialahmadi, Bruno Lopez, Philippe Berio +7
Studying the physical conditions structuring the young circumstellar disks is required for understanding the onset of planet formation. Of particular interest is the protoplanetary…
A ghostly damped Ly system revealed by metal absorption lines
Hassan Fathivavsari, Patrick Petitjean, Siwei Zou +4
We report the discovery of the first 'ghostly' damped Ly absorption system (DLA), which is identified by the presence of absorption from strong low-ion species at $z_{\rm abs}=1…
Extended Ly emission around quasars with eclipsing damped Ly systems
Hassan Fathivavsari, Patrick Petitjean, Pasquier Noterdaeme +4
We present spectroscopic observations of six high redshift ( 2) quasars, which have been selected for their Lyman (Ly) emission region being only partially c…
A coronagraphic absorbing cloud reveals the narrow-line region and extended Lyman- emission of QSO J0823+0529
Hassan Fathivavsari, Patrick Petitjean, Pasquier Noterdaeme +5
We report long-slit spectroscopic observations of the quasar SDSS J082303.22+052907.6 (3.1875), whose Broad Line Region (BLR) is partly eclipsed by a strong damp…
Spectral atlases of the Sun from 3980 to 7100 Å at the center and at the limb
Hassan Fathivavsari, Ali Ajabshirizadeh, Serge Koutchmy
In this work, we present digital and graphical atlases of spectra of both the solar disk-center and of the limb near the Solar poles using data taken at the UTS-IAP & RIAAM (the Un…
An investigation of the line of sight towards QSO PKS 0237-233
H. Fathivavsari, P. Petitjean, C. Ledoux +4
We present a detailed analysis of absorption systems along the line of sight towards QSO PKS 0237-233 using a high resolution spectrum of signal-to-noise ratio (SNR) ~ 60-80 obtain…
The UVES Large Program for Testing Fundamental Physics II: Constraints on a Change in μ Towards Quasar HE 0027-1836
H. Rahmani, M. Wendt, R. Srianand +14
We present an accurate analysis of the H2 absorption lines from the zabs ~ 2.4018 damped Lyα system towards HE 0027-1836 observed with the Very Large Telescope Ultraviolet and Visu…