Publications (51)
The First Luminous Quasars and Their Host Galaxies
Xiaohui Fan, Aaron Barth, Eduardo Banados +26
The discovery of luminous quasars at redshifts up to 7.5 demonstrates the existence of several billion M_sun supermassive black holes (SMBHs) less than a billion years after the Bi…
ESpRESSO -- Forward modeling Roman Space Telescope spectroscopy
Austen Gabrielpillai, Isak G. B. Wold, Sangeeta Malhotra +4
We describe the software package - [E]xtragalactic [Sp]ectroscopic [R]oman [E]mulator and [S]imulator of [S]ynthetic [O]bjects, created to emulate the slitless…
Formation of Metal-Poor Globular Clusters in Lyman alpha Emitting Galaxies in the Early Universe
Bruce G. Elmegreen, Sangeeta Malhotra, James Rhoads
The size, mass, luminosity, and space density of Lyman-alpha emitting (LAE) galaxies observed at intermediate to high redshift agree with expectations for the properties of galaxie…
Galaxy Assembly and SMBH/AGN-growth from Cosmic Dawn to the End of Reionization
Rolf A. Jansen, Rogier Windhorst, James Rhoads +5
[abridged] We propose a tiered, UV--near-IR, cosmological broad- and medium-band imaging and grism survey that covers ~10 deg^2 in two epochs to m_AB=28, ~3 deg^2 in seven epochs t…
Luminosity functions of Lyman-alpha emitters at z=6.5, and z=5.7: evidence against reionization at z=6
Sangeeta Malhotra, James Rhoads
Lyman-alpha emission from galaxies should be suppressed completely or partially at redshifts beyond reionization. Without knowing the instrinsic properties of galaxies at z = 6.5,…
Early-type galaxies in the PEARS survey: Probing the stellar populations at moderate redshift
Ignacio Ferreras, Anna Pasquali, Sangeeta Malhotra +10
Using HST/ACS slitless grism spectra from the PEARS program, we study the stellar populations of morphologically selected early-type galaxies in the GOODS North and South fields. T…
The Expected Detection of Dust Emission from High-Redshift Lyman Alpha Galaxies
Steven Finkelstein, Sangeeta Malhotra, James Rhoads +2
Recent results have shown that a substantial fraction of high-redshift Lyman alpha galaxies contain considerable amounts of dust. This implies that Lyman alpha galaxies are not pri…
ATLAS Probe: Breakthrough Science of Galaxy Evolution, Cosmology, Milky Way, and the Solar System
Yun Wang, Massimo Robberto, Mark Dickinson +37
ATLAS (Astrophysics Telescope for Large Area Spectroscopy) Probe is a concept for a NASA probe-class space mission. It is the follow-up space mission to WFIRST, boosting its scient…
LAGER Ly Luminosity Function at , Implications for Reionization
Isak G. B. Wold, Sangeeta Malhotra, James Rhoads +17
We present a new measurement of the Ly luminosity function at redshift , finding moderate evolution from that is consistent with a fully or largely ionized $z\si…
Prompt Ia Supernovae Are Significantly Delayed
Cody Raskin, Evan Scannapieco, James Rhoads +1
The time delay between the formation of a population of stars and the onset of type Ia supernovae (SNe Ia) sets important limits on the masses and nature of SN Ia progenitors. Here…
The atomic gas properties of Green Pea galaxies: Connections to Lyman continuum leakage
Archishman Khasnovis, Nissim Kanekar, Sangeeta Malhotra +1
We have used the Green Bank Telescope to search for H{\sc{i}} 21\,cm emission from 30 Green Pea galaxies (GPs) at , obtaining 7 detections of H{\sc{i}} 21\,cm…
The GLARE Survey II. Faint z=6 Ly-alpha Line Emitters in the HUDF
Elizabeth R Stanway, Andrew J Bunker, Karl Glazebrook +6
The galaxy population at z~6 has been the subject of intense study in recent years, culminating in the Hubble Ultra Deep Field (HUDF) -- the deepest imaging survey yet. A large num…
Improved Photometric Redshifts with Surface Luminosity Priors
Lifang Xia, Seth Cohen, Sangeeta Malhotra +6
We apply Bayesian statistics with prior probabilities of galaxy surface luminosity (SL) to improve photometric redshifts. We apply the method to a sample of 1266 galaxies with spec…
Searching for z~7.7 Lyman Alpha Emitters in the COSMOS Field with NEWFIRM
Hannah Krug, Sylvain Veilleux, Vithal Tilvi +8
The study of Ly-alpha emission in the high-redshift universe is a useful probe of the epoch of reionization, as the Ly-alpha line should be attenuated by the intergalactic medium (…
Observing Galaxy Evolution in the Context of Large-Scale Structure
Mark Dickinson, Yun Wang, James Bartlett +26
Galaxies form and evolve in the context of their local and large-scale environments. Their baryonic content that we observe with imaging and spectroscopy is intimately connected to…
Large Area Lyman Alpha survey: finding young galaxies at z=4.5
Sangeeta Malhotra, James Rhoads, Arjun Dey +3
Strong Lyman-alpha emission is a signpost of young stars and the absence of dust and thus indicates young galaxies. To find such a population of young galaxies at z=4.5 we started…
The Hubble Deep Hydrogen Alpha (HDH) Project: I. Catalog of Emission-line Galaxies
Shuairu Zhu, Zhen-Ya Zheng, James Rhoads +14
We present the first results of the Hubble Deep Hydrogen Alpha (HDH) project, which analyzes the space-borne deep H narrowband imaging data in the GOODS-S region. The HDH$Î…
Cosmic Dawn and Reionization: Astrophysics in the Final Frontier
Asantha Cooray, James Aguirre, Yacine Ali-Haimoud +71
The cosmic dawn and epoch of reionization mark the time period in the universe when stars, galaxies, and blackhole seeds first formed and the intergalactic medium changed from neut…
Metallicities of Emission-Line Galaxies from HST ACS PEARS and HST WFC3 ERS Grism Spectroscopy at 0.6 < z < 2.4
Lifang Xia, Sangeeta Malhotra, James Rhoads +9
Galaxies selected on the basis of their emission line strength show low metallicities, regardless of their redshifts. We conclude this from a sample of faint galaxies at redshifts…
Texas Spectroscopic Search for Ly Emission at the End of Reionization II. The Deepest Near-Infrared Spectroscopic Observation at
Intae Jung, Steven L. Finkelstein, Mark Dickinson +12
Realizing the utility of Ly emission to trace the evolution of the intergalactic medium (IGM) during the epoch of reionization requires deep spectroscopy across the boundary of…
First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7
Zhen-Ya Zheng, Junxian Wang, James Rhoads +12
We present the first results from the ongoing LAGER project (Lyman Alpha Galaxies in the Epoch of Reionization), which is the largest narrowband survey for 7 galaxies to d…
Spectroscopic Study of the HST/ACS PEARS Emission-Line Galaxies
Lifang Xia, Sangeeta Malhotra, James Rhoads +6
We present spectroscopy of 76 emission-line galaxies (ELGs) in CDF-S taken with the LDSS3 spectrograph on Magellan Telescope. These galaxies are selected to have emission lines wit…
Real or Interloper? The Redshift Likelihoods of z>8 Galaxies in the HUDF12
Nor Pirzkal, Barry Rothberg, Russell Ryan +4
In the absence of spectra, fitting template model spectra to observed photometric fluxes, known as Spectral Energy Distribution (SED) fitting, has become the workhorse for identify…
Astro2020 Science White Paper: A proposal to exploit galaxy-21cm synergies to shed light on the Epoch of Reionization
Anne Hutter, Pratika Dayal, Sangeeta Malhotra +26
This white paper highlights the crucial and urgent synergies required between WFIRST, Subaru Hyper Suprime-Cam or other >25m-class telescopes galaxy observations and SKA 21cm measu…
A Two-Dimensional Spectroscopic Study of Emission Line Galaxies in the Faint Infrared Grism Survey (FIGS) I: Detection Method and Catalog
Norbert Pirzkal, Barry Rothberg, Russell E. Ryan +31
We present the results from the application of a two-dimensional emission line detection method, EMission-line two-Dimensional (EM2D), to the near-infrared G102 grism observations…
Exploring the NRO Opportunity for a Hubble-sized Wide-field Near-IR Space Telescope -- NEW WFIRST
Alan Dressler, David Spergel, Matt Mountain +24
We discuss scientific, technical and programmatic issues related to the use of an NRO 2.4m telescope for the WFIRST initiative of the 2010 Decadal Survey. We show that this impleme…
Large Equivalent width Lyman-alpha line emission at z=4.5: young galaxies in a young universe
Sangeeta Malhotra, James Rhoads
The Large Area Lyman Alpha survey has found ~ 150 Lyman-alpha emitters at z=4.5. While stellar models predict a maximum Lyman-alpha equivalent width (EW) of 240 angstrom, 60% of th…
New spectroscopic confirmations of Lyman- emitters at z 7 from the LAGER survey
Santosh Harish, Isak G. B. Wold, Sangeeta Malhotra +14
We report spectroscopic confirmations of 15 Lyman-alpha galaxies at , implying a spectroscopic confirmation rate of 80% on candidates selected from LAGER (Lyman-Alpha…
Discovery of a z = 7.452 High Equivalent Width Lyman-α Emitter from the Hubble Space Telescope Faint Infrared Grism Survey
Rebecca L. Larson, Steven L. Finkelstein, Norbert Pirzkal +18
We present the results of an unbiased search for Lyα emission from continuum-selected 6 < z < 8 galaxies. Our dataset consists of 160 orbits of G102 slitless grism spectroscopy ob…
Three Lyman-alpha Emitters at z approx 6: Early GMOS/Gemini Data from the GLARE Project
Elizabeth R. Stanway, Karl Glazebrook, Andrew J. Bunker +14
We report spectroscopic detection of three z~6 Lyman-alpha emitting galaxies, in the vicinity of the Hubble Ultra Deep Field, from the early data of the Gemini Lyman- at Reioni…
Near-Infrared Spectroscopy of Galaxies During Reionization: Measuring CIII] in a Galaxy at
Taylor A. Hutchison, Casey Papovich, Steven L. Finkelstein +9
We present Keck/MOSFIRE -band spectroscopy targeting CIII] 1907,1909 in a galaxy previously identified via Ly emission. We detect strong line emission at…
Bubble mapping with the Square Kilometer Array -- I. Detecting galaxies with Euclid, JWST, WFIRST and ELT within ionized bubbles in the intergalactic medium at z>6
Erik Zackrisson, Suman Majumdar, Rajesh Mondal +16
The Square Kilometer Array is expected to provide the first tomographic observations of the neutral intergalactic medium at redshifts z>6 and pinpoint the locations of individual i…
Texas Spectroscopic Search for Ly Emission at the End of Reionization III. the Ly Equivalent-width Distribution and Ionized Structures at
Intae Jung, Steven L. Finkelstein, Mark Dickinson +11
Ly emission from galaxies can be utilized to characterize the ionization state in the intergalactic medium (IGM). We report our search for Ly emission at using a comp…
ATLAS Probe: Breakthrough Science of Galaxy Evolution, Cosmology, Milky Way, and the Solar System
Yun Wang, Mark Dickinson, Lynne Hillenbrand +45
ATLAS (Astrophysics Telescope for Large Area Spectroscopy) is a concept for a NASA probe-class space mission. It is the spectroscopic follow-up mission to WFIRST, boosting its scie…
Strong [OIII]H emitters dominated the ionizing budget at
Isak Wold, Sangeeta Malhotra, James Rhoads
We quantify the ionizing photon production at using the deepest spectroscopically confirmed sample of strong [OIII]H emitters (rest-frame EW A) in the Abell 2…
Spectrophotometric Redshifts In The Faint Infrared Grism Survey: Finding Overdensities Of Faint Galaxies
John Pharo, Sangeeta Malhotra, James Rhoads +19
We improve the accuracy of photometric redshifts by including low-resolution spectral data from the G102 grism on the Hubble Space Telescope, which assists in redshift determinatio…
The road to the red sequence: A detailed view of the formation of a massive galaxy at z~2
Ignacio Ferreras, Anna Pasquali, Sadegh Khochfar +7
(Abridged) We present here a detailed analysis of the star formation history (SFH) of FW4871, a massive galaxy at z=1.893+-0.002. We compare rest-frame optical and NUV slitless gri…
Infrared and Optical Observations of GRB 030115 and its Extremely Red Host Galaxy: Implications for Dark Bursts
Andrew Levan, Andrew Fruchter, James Rhoads +24
We present near-infrared (nIR) and optical observations of the afterglow of GRB 030115. Discovered in an infrared search at Kitt Peak 5 hours after the burst trigger, this afterglo…
Conditions for detecting lensed Population III galaxies in blind surveys with the James Webb Space Telescope, the Roman Space Telescope and Euclid
Anton Vikaeus, Erik Zackrisson, Daniel Schaerer +5
Dark matter halos that reach the HI-cooling mass without prior star formation or external metal pollution represent potential sites for the formation of small - extremely faint - P…
FIGS -- Faint Infrared Grism Survey: Description and Data Reduction
Norbert Pirzkal, Sangeeta Malhotra, Russell E. Ryan +26
The Faint Infrared Grism Survey (FIGS) is a deep Hubble Space Telescope (HST) WFC3/IR (Wide Field Camera 3 Infrared) slitless spectroscopic survey of four deep fields. Two fields a…
A Deep Search with HST for Late Time Supernova Signatures in the Hosts of XRF 011030 and XRF 020427
Andrew Levan, Sandeep Patel, Chryssa Kouveliotou +16
X-ray Flashes (XRFs) are, like Gamma-Ray Bursts (GRBs), thought to signal the collapse of massive stars in distant galaxies. Many models posit that the isotropic equivalent energie…
Emission Line Metallicities From The Faint Infrared Grism Survey and VLT/MUSE
John Pharo, Sangeeta Malhotra, James Rhoads +20
We derive direct measurement gas-phase metallicities of for 14 low-mass Emission Line Galaxies (ELGs) at identified in the Faint Infrar…
The Star Formation Camera
Paul A. Scowen, Rolf Jansen, Matthew Beasley +21
The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV/optical dichroic camera designed for the Theia 4-m space-borne space…
First Spectroscopic Confirmations of z ~ 7.0 Lya Emitting Galaxies in the LAGER Survey
Weida Hu, Junxian Wang, Zhenya Zheng +16
Narrowband imaging is a highly successful approach for finding large numbers of high redshift Lya emitting galaxies (LAEs) up to z~6.6. However, at z>~7 there are as yet only 3 nar…
The Wide Field Infrared Survey Telescope: 100 Hubbles for the 2020s
Rachel Akeson, Lee Armus, Etienne Bachelet +103
The Wide Field Infrared Survey Telescope (WFIRST) is a 2.4m space telescope with a 0.281 deg^2 field of view for near-IR imaging and slitless spectroscopy and a coronagraph designe…
A Link to the Past: Using Markov Chain Monte Carlo Fitting to Constrain Fundamental Parameters of High-Redshift Galaxies
N. Pirzkal, B. Rothberg, Kim K. Nilsson +4
We have a developed a new method for fitting spectral energy distributions (SEDs) to identify and constrain the physical properties of high-redshift (4 < z < 8) galaxies. Our appro…
Going Wide and Deep with Roman: The z~6-9 UV luminosity function in a Roman Deep Field
Micaela B. Bagley, Steven L. Finkelstein, James Rhoads +4
We present a trade study of possible ultra-deep surveys with the Nancy Grace Roman Space Telescope, optimizing the depth-area-filter parameter space for high-redshift galaxy scienc…
Using Spatial Distributions to Constrain Progenitors of Supernovae and Gamma Ray Bursts
Cody Raskin, Evan Scannapieco, James Rhoads +1
We carry out a comprehensive theoretical examination of the relationship between the spatial distribution of optical transients and the properties of their progenitor stars. By con…
The Volume Fraction of Ionized Intergalactic Gas at Redshift z=6.5
Sangeeta Malhotra, James Rhoads
The observed number density of Lyman-alpha sources implies a minimum volume of the inter-galactic medium that must be ionized, in order to allow the Lyman-alpha photons to escape a…
FIGS: Spectral fitting constraints on the star formation history of massive galaxies since Cosmic Noon
Ignacio Ferreras, Anna Pasquali, Nor Pirzkal +16
We constrain the stellar population properties of a sample of 52 massive galaxies, with stellar mass log Ms>10.5, over the redshift range 0.5<z<2 by use of observer-frame optical a…
Emission-Line Galaxies from the PEARS Hubble Ultra Deep Field: A 2-D Detection Method and First Results
Amber N. Straughn, Gerhardt R. Meurer, Norbert Pirzkal +11
The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) grism PEARS (Probing Evolution And Reionization Spectroscopically) survey provides a large dataset of low-resolut…