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We present the first large, blind and uniformly selected survey for molecular hydrogen (H_2) in damped Lyman alpha systems (DLAs) with moderate-to-high resolution spectra. 86 DLAs were searched for absorption in the many Lyman and Werner…

Astrophysics of Galaxies · Physics 2015-06-22 Regina A. Jorgenson , Michael T. Murphy , Rodger Thompson , Robert F. Carswell

We present zELDA(redshift Estimator for Line profiles of Distant Lyman-Alpha emitters), an open source code to fit Lyman-Alpha (Lya) line profiles. The main motivation is to provide the community with an easy to use and fast tool to analyze…

Astrophysics of Galaxies · Physics 2021-12-22 Siddhartha Gurung-Lopez , Max Gronke , Shun Saito , Silvia Bonoli , Alvaro A. Orsi

The recently discovered population of ultra-faint extended line emitters can account for the majority of the incidence rate of Damped Lyman Alpha systems (DLAs) at z ~ 3 if the line emission is interpreted as Ly alpha. We show here that a…

Astrophysics · Physics 2011-01-19 Luke A. Barnes , Martin G. Haehnelt

Damped Ly-alpha Systems (DLAs), with N(HI)>2*10^20 cm^{-2}, observed in quasars have allowed us to quantify the chemical content of the Universe over cosmological scales. Such studies can be extended to lower N(HI), in the sub-DLA range…

We examine the kinematic structure of Damped Lyman-alpha Systems (DLAs) in a series of cosmological hydrodynamic simulations using the AREPO code. We are able to match the distribution of velocity widths of associated low ionisation metal…

Astrophysics of Galaxies · Physics 2015-01-08 Simeon Bird , Martin Haehnelt , Marcel Neeleman , Shy Genel , Mark Vogelsberger , Lars Hernquist

Using a sample of 100 H I - selected damped Lyman alpha (DLA) systems, observed with the High Resolution Echelle Spectrometer on the Keck I telescope, we present evidence that the scatter in the well-studied correlation between the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-07 Marcel Neeleman , Arthur M. Wolfe , J. Xavier Prochaska , Marc Rafelski

We report Giant Metrewave Radio Telescope (GMRT) 21cm observations of two confirmed and one candidate low redshift damped Lyman-alpha systems (DLAS). HI absorption was detected in the two confirmed systems, at z=0.2378 and z=0.5247, with…

Astrophysics · Physics 2009-11-06 Nissim Kanekar , Jayaram N. Chengalur

We have searched the Sloan Digital Sky Survey Data Release 12 for ghostly Damped Ly$\alpha$ (DLA) systems. These systems, located at the redshift of the quasars, show strong absorption from low-ionization atomic species but reveal no HI…

Astrophysics of Galaxies · Physics 2020-01-15 Hassan Fathivavsari

The advantages of angular differential imaging (ADI) has been previously untested in imaging the host galaxies of damped Lyman alpha (DLA) systems. In this pilot study, we present the first application of ADI to directly imaging the host…

Astrophysics of Galaxies · Physics 2017-06-21 Mara Johnson-Groh , Christian Marois , Sara L. Ellison

We report Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet and Arecibo Telescope H{\sc i} 21cm spectroscopic studies of six damped and sub-damped Lyman-$\alpha$ absorbers (DLAs and sub-DLAs, respectively) at $z \lesssim…

Astrophysics of Galaxies · Physics 2017-11-29 Nissim Kanekar , Marcel Neeleman , J. Xavier Prochaska , Tapasi Ghosh

We report a new technique to select 1.6<z<4.6 dusty Lyman-alpha emitters (LAEs), over a third of which are `blobs' (LABs) with emission extended on scales of 30-100kpc. Combining data from the NASA Wide-field Infrared Survey Explorer (WISE)…

We employ observationally determined intrinsic velocity widths and column densities of damped Lyman-alpha systems at high redshift to investigate the distribution of baryons in protogalaxies within the context of a standard cold dark matter…

Astrophysics · Physics 2009-10-30 Karsten Jedamzik , Jason X. Prochaska

A powerful technique to trace the signatures of the first stars is through the metal enrichment in concentrated reservoirs of hydrogen, such as the damped Lyman-alpha absorbers (DLAs) in the early universe. We conducted a survey aimed at…

Astrophysics of Galaxies · Physics 2025-10-01 Jianghao Huyan , Varsha P. Kulkarni , Suraj Poudel , Nicolas Tejos , Celine Peroux , Sebastian Lopez

We have updated and applied a convolutional neural network (CNN) machine learning model to discover and characterize damped Ly$\alpha$ systems (DLAs) based on Dark Energy Spectroscopic Instrument (DESI) mock spectra. We have optimized the…

Using the GAEA semi-analytic model, we analyse the connection between Damped Lyman-$\alpha$ systems (DLAs) and HI in galaxies. Our state-of-the-art semi-analytic model is tuned to reproduce the local galaxy HI mass function, and that also…

Astrophysics of Galaxies · Physics 2020-08-12 Serafina Di Gioia , Stefano Cristiani , Gabriella De Lucia , Lizhi Xie

We present the largest homogeneous survey of $z>4.4$ damped Lyman-$\alpha$ systems (DLAs) using the spectra of 163 QSOs that comprise the Giant Gemini GMOS (GGG) survey. With this survey we make the most precise high-redshift measurement of…

We report results from a deep search for redshifted HI 21cm absorption from eight damped Lyman-$\alpha$ absorbers (DLAs) detected in our earlier optical survey for DLAs towards radio-loud quasars. HI 21cm absorption was detected from the $z…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Nissim Kanekar , Sara L. Ellison , Emmanuel Momjian , Brian A. York , Max Pettini

Context: Wide-field narrowband surveys are an efficient way of searching large volumes of high-redshift space for distant galaxies. Aims: We describe the Wide Field Imager Lyman-Alpha Search (WFILAS) over 0.74 sq. degree for bright…

We present the chemical abundance measurements of the first large, medium-resolution, uniformly selected damped Lyman alpha system (DLA) survey. The sample contains 99 DLAs towards 89 quasars selected from the SDSS DR5 DLA sample in a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Regina A. Jorgenson , Michael T. Murphy , Rodger Thompson

The H~{\sc i} gas distribution in damped Lyman $\alpha$ absorbers (DLAs) has remained elusive due to the point-source nature of background quasar emission. Observing DLAs against spatially extended background galaxies provides a new method…