分类： 天文学 >> 天文学 提交时间： 2023-02-19
Vandana Ramakrishnan
Byeongha Moon
Sang Hyeok Im
Rameen Farooq
Kyoung-Soo Lee
Eric Gawiser
Yujin Yang
Changbom Park
Ho Seong Hwang
Francisco Valdes
Maria Celeste Artale
Robin Ciardullo
Arjun Dey
Caryl Gronwall
Lucia Guaita
Woong-Seob Jeong
Nelson Padilla
Akriti Singh
Ann Zabludoff
摘要： While many Lyman-alpha Blobs (LABs) are found in and around several well-known protoclusters at high redshift, how they trace the underlying large-scale structure is still poorly understood. In this work, we utilize 5,352 Lyman-alpha emitters (LAEs) and 129 LABs at z=3.1 identified over a $\sim$ 9.5 sq. degree area in early data from the ongoing One-hundred-deg$^2$ DECam Imaging in Narrowbands (ODIN) survey to investigate this question. Using LAEs as tracers of the underlying matter distribution, we identify overdense structures as galaxy groups, protoclusters, and filaments of the cosmic web. We find that LABs preferentially reside in regions of higher-than-average density and are located in closer proximity to overdense structures, which represent the sites of protoclusters and their substructures. Moreover, protoclusters hosting one or more LABs tend to have a higher descendant mass than those which do not. Blobs are also strongly associated with filaments of the cosmic web, with $\sim$ 70% of the population being within a projected distance of 2.4 pMpc from a filament. We show that the proximity of LABs to protoclusters is naturally explained by their association with filaments as large cosmic structures are where many filaments converge. The contiguous wide-field coverage of the ODIN survey allows us for the first time to firmly establish a connection between LABs as a population and their environment.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Chenxu Liu
Karl Gebhardt
Wolfram Kollatschny
Robin Ciardullo
Erin Mentuch Cooper
Dustin Davis
Daniel J. Farrow
Steven L. Finkelstein
Eric Gawiser
Caryl Gronwall
Gary J. Hill
Lindsay House
Donald P. Schneider
Tanya Urrutia
Gregory R. Zeimann
摘要： We report an Active Galactic Nucleus (AGN) with extremely high equivalent width (EW), EW(LyA+NV,rest)>921 AA in the rest-frame, at z~2.24 in the Hobby-Eberly Telescope Dark Energy Experiment Survey (HETDEX) as a representative case of the high EW AGN population. The continuum level is a non-detection in the HETDEX spectrum, thus the measured EW is a lower limit. The source is detected with significant emission lines (>7sigma) at LyA+NV, CIV, and moderate emission line (~4sigma) at HeII within the wavelength coverage of HETDEX (3500 AA - 5500 AA). The r-band magnitude is 24.57 from the Hyper Suprime-Cam-HETDEX joint survey with a detection limit of r=25.12 at 5sigma. The LyA emission line spans a clearly resolved region of ~10 arcsec (85 kpc) in diameter. The LyA line profile is strongly double peaked. The spectral decomposed blue gas and red gas Ly$\alpha$ emission are separated by ~1.2 arcsec (10.1 kpc) with a line-of-sight velocity offset of ~1100 km/s. This source is probably an obscured AGN with powerful winds.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Chenxu Liu
Karl Gebhardt
Wolfram Kollatschny
Robin Ciardullo
Erin Mentuch Cooper
Dustin Davis
Daniel J. Farrow
Steven L. Finkelstein
Eric Gawiser
Caryl Gronwall
Gary J. Hill
Lindsay House
Donald P. Schneider
Tanya Urrutia
Gregory R. Zeimann
摘要： We report an Active Galactic Nucleus (AGN) with extremely high equivalent width (EW), EW(LyA+NV,rest)>921 AA in the rest-frame, at z~2.24 in the Hobby-Eberly Telescope Dark Energy Experiment Survey (HETDEX) as a representative case of the high EW AGN population. The continuum level is a non-detection in the HETDEX spectrum, thus the measured EW is a lower limit. The source is detected with significant emission lines (>7sigma) at LyA+NV, CIV, and moderate emission line (~4sigma) at HeII within the wavelength coverage of HETDEX (3500 AA - 5500 AA). The r-band magnitude is 24.57 from the Hyper Suprime-Cam-HETDEX joint survey with a detection limit of r=25.12 at 5sigma. The LyA emission line spans a clearly resolved region of ~10 arcsec (85 kpc) in diameter. The LyA line profile is strongly double peaked. The spectral decomposed blue gas and red gas Ly$\alpha$ emission are separated by ~1.2 arcsec (10.1 kpc) with a line-of-sight velocity offset of ~1100 km/s. This source is probably an obscured AGN with powerful winds.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Dustin Davis
Karl Gebhardt
Erin Mentuch Cooper
Robin Ciardullo
Maximilian Fabricius
Daniel J. Farrow
John J. Feldmeier
Steven L. Finkelstein
Eric Gawiser
Caryl Gronwall
Gary J. Hill
Ulrich Hopp
Lindsay R. House
Donghui Jeong
Wolfram Kollatschny
Eiichiro Komatsu
Martin Landriau
Chenxu Liu
Shun Saito
Sarah Tuttle
摘要： The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is an untargeted spectroscopic survey that aims to measure the expansion rate of the Universe at $z \sim 2.4$ to 1% precision for both $H(z)$ and $D_A(z)$. HETDEX is in the process of mapping in excess of one million Lyman Alpha emitting (LAE) galaxies and a similar number of lower-z galaxies as a tracer of the large-scale structure. The success of the measurement is predicated on the post-observation separation of galaxies with Ly$\alpha$ emission from the lower-$z$ interloping galaxies, primarily [OII], with low contamination and high recovery rates. The Emission Line eXplorer (ELiXer) is the principal classification tool for HETDEX, providing a tunable balance between contamination and completeness as dictated by science needs. By combining multiple selection criteria, ELiXer improves upon the 20 Angstrom rest-frame equivalent width cut commonly used to distinguish LAEs from lower-$z$ [OII] emitting galaxies. Despite a spectral resolving power, R $\sim800$, that cannot resolve the [OII] doublet, we demonstrate the ability to distinguish LAEs from foreground galaxies with 98.1% accuracy. We estimate a contamination rate of Ly$\alpha$ by [OII] of 1.2% and a Ly$\alpha$ recovery rate of 99.1% using the default ELiXer configuration. These rates meet the HETDEX science requirements.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Chenxu Liu
Karl Gebhardt
Erin Mentuch Cooper
Yechi Zhang
Donald P. Schneider
Robin Ciardullo
Dustin Davis
Daniel J. Farrow
Steven L. Finkelstein
Caryl Gronwall
Gary J. Hill
Lindsay House
Donghui Jeong
Wolfram Kollatschny
Maja Lujan Niemeyer
Sarah Tuttle
摘要： We present the LyA emission line luminosity function (LF) of the Active
Galactic Nuclei (AGN) in the first release of the Hobby-Eberly Telescope Dark
Energy Experiment Survey (HETDEX) AGN catalog (Liu et al. 2022, Paper I). The
AGN are selected either by emission-line pairs characteristic of AGN or by
single broad emission line, free of any photometric pre-selections
(magnitude/color/morphology). The sample consists of 2,346 AGN spanning
1.885\sigma$ confidence at r~26 in the deepest
$r$-band images we have searched. The LyA line luminosity ranges from ~10^42.3
to ~10^45.9 erg s^-1. Our LyA LF shows a turnover luminosity with opposite
slopes on the bright end and the faint end: The space density is highest at
L_LyA^*=10^43.4 erg s^-1.
We explore the evolution of the AGN LF over a broader redshift range
(0.8
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Erin Mentuch Cooper
Karl Gebhardt
Dustin Davis
Daniel J. Farrow
Chenxu Liu
Gregory Zeimann
Robin Ciardullo
John J. Feldmeier
Niv Drory
Donghui Jeong
Barbara Benda
William P. Bowman
Michael Boylan-Kolchin
Oscar A. Chavez Ortiz
Maya H. Debski
Mona Dentler
Maximilian Fabricius
Rameen Farooq
Steven L. Finkelstein
Eric Gawiser
摘要： We present the first publicly released catalog of sources obtained from the
Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). HETDEX is an integral
field spectroscopic survey designed to measure the Hubble expansion parameter
and angular diameter distance at 1.88
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Chenxu Liu
Karl Gebhardt
Erin Mentuch Cooper
Dustin Davis
Donald P. Schneider
Robin Ciardullo
Daniel J. Farrow
Steven L. Finkelstein
Caryl Gronwall
Yuchen Guo
Gary J. Hill
Lindsay House
Donghui Jeong
Shardha Jogee
Wolfram Kollatschny
Mirko Krumpe
Martin Landriau
Oscar A Chavez Ortiz
Yechi Zhang
摘要： We present the first Active Galactic Nuclei (AGN) catalog in the Hobby-Eberly Telescope Dark Energy Experiment Survey (HETDEX) observed between January 2017 and June 2020. HETDEX is an ongoing spectroscopic survey with no pre-selection based on magnitudes, colors or morphologies, enabling us to select AGN based on their spectral features. Both luminous quasars and low-luminosity Seyferts are found in our catalog. AGN candidates are selected with at least two significant AGN emission lines, such as the LyA and CIV line pair, or with single broad emission lines (FWHM > 1000 km/s). Each source is further confirmed by visual inspections. This catalog contains 5,322 AGN, covering an effective sky coverage of 30.61 deg^2. A total of 3,733 of these AGN have secure redshifts, and we provide redshift estimates for the remaining 1,589 single broad-line AGN with no cross matched spectral redshifts from SDSS DR14Q. The redshift range of the AGN catalog is 0.25 22.5, and 2.6% reaching the detection limit at r ~ 26 mag of the deepest imaging surveys we searched. We also provide a composite spectrum of the AGN sample covering 700 AA - 4400 AA.
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