Alaina Henry
A5087399697- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- CCD and CMOS Imaging Sensors
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Scientific Research and Discoveries
- Radio Astronomy Observations and Technology
- Spectroscopy and Laser Applications
- Photocathodes and Microchannel Plates
- Particle Detector Development and Performance
- Atmospheric and Environmental Gas Dynamics
- Sensor Technology and Measurement Systems
- Advanced Semiconductor Detectors and Materials
- Calibration and Measurement Techniques
- Geophysics and Gravity Measurements
- Pulsars and Gravitational Waves Research
- Solar and Space Plasma Dynamics
- Spectroscopy and Chemometric Analyses
- Particle Accelerators and Free-Electron Lasers
- Cosmology and Gravitation Theories
Space Telescope Science Institute
2017-2025
Johns Hopkins University
2018-2024
Ludwig-Maximilians-Universität München
2024
Pennsylvania State University
2024
Stockholm University
2022
Goddard Space Flight Center
2013-2020
Deleted Institution
2013-2020
University of California, Santa Barbara
2010-2013
National Postdoctoral Association
2013
University of California, Los Angeles
2003-2009
We constrain the slope of star formation rate (SFR; log Ψ) to stellar mass (log M⋆) relation down (M⋆/M☉) = 8.4 9.2) at z 0.5 (z 2.5) with a mass-complete sample 39,106 star-forming galaxies selected from 3D-HST photometric catalogs, using deep photometry in CANDELS fields. For first time, we find that is dependent on mass, such it steeper low masses Ψ∝log than high Ψ∝(0.3–0.6)log M⋆). These low-mass slopes are found for three different indicators: combination ultraviolet (UV) and infrared...
We report Hubble Space Telescope/Cosmic Origins Spectrograph observations of the Lyα emission and interstellar absorption lines in a sample 10 star-forming galaxies at z ∼ 0.2. Selected on basis high equivalent width optical lines, sample, dubbed "Green Peas," make some best analogs for young an early universe. detect all ten galaxies, 9/10 show double-peaked line profiles suggestive low H i column density. measure Lyα/Hα flux ratios 0.5–5.6, implying that 5%–60% photons escape galaxies....
The GLASS James Webb Space Telescope Early Release Science (hereafter GLASS-JWST-ERS) Program will obtain and make publicly available the deepest extragalactic data of ERS campaign. It is primarily designed to address two key science questions, namely, "what sources ionized universe when?" "how do baryons cycle through galaxies?", while also enabling a broad variety first look scientific investigations. In primary mode, it NIRISS NIRSpec spectroscopy galaxies lensed by foreground Hubble...
Abstract Detections and non-detections of Lyman alpha (Lyα) emission from z > 6 galaxies (<1 Gyr after the big bang) can be used to measure timeline cosmic reionization. Of key interest measuring reionization’s mid-stages, but also increasing observational challenge, are observations at 7, where Lyα redshifts near infra-red wavelengths. Here we present a search for 7.2 in 53 intrinsically faint Break Galaxy candidates, gravitationally lensed by massive galaxy clusters, KMOS...
Abstract The James Webb Space Telescope (JWST) Early Release Observations (EROs) is a set of public outreach products created to mark the end commissioning and beginning science operations for JWST. Colloquially known as “Webb First Images Spectra,” these were intended demonstrate worldwide that JWST ready science, capable producing spectacular results. package was released on 2022 July 12 included images spectra galaxy cluster SMACS J0723.3-7327 distant lensed galaxies, interacting group...
We provide an overview of the capabilities and performance Near-Infrared Spectrograph (NIRSpec) on James Webb Space Telescope (JWST) when used in its multi-object spectroscopy (MOS) mode employing a novel Micro Shutter Array (MSA) slit device. The MSA consists four separate 98 arcsec $\times$ 91 quadrants each containing $365\times171$ individually addressable shutters whose open areas sky measure 0.20 0.46 0.27 0.53 pitch. This is first time that configurable spectrograph has been available...
Abstract The origins of Lyman continuum (LyC) photons responsible for the reionization universe are as yet unknown and highly contested. Detecting LyC from Epoch Reionization is not possible due to absorption by intergalactic medium, which has prompted development several indirect diagnostics infer rate at galaxies contribute reionize studying lower-redshift analogs. We present Low-redshift Continuum Survey (LzLCS) comprising measurements made with Hubble Space Telescope Cosmic Origins...
The Lyman continuum (LyC) cannot be observed at the epoch of reionization (z {\gtrsim} 6) due to intergalactic H I absorption. To identify emitters (LCEs) and infer fraction escaping LyC, astronomers have developed various indirect diagnostics LyC escape. Using measurements from Low-redshift Continuum Survey (LzLCS), we present first statistical test these diagnostics. While optical depth indicators based on Lyα, such as peak velocity separation equivalent width, perform well, also find that...
ABSTRACT Most of the hydrogen in intergalactic medium (IGM) was rapidly ionized at high redshifts. While observations have established that reionization occurred, observational constraints on high-redshift ionizing emissivity remain elusive. Here, we present a new analysis Low-redshift Lyman Continuum Survey (LzLCS) and literature observations, combined sample 89 star-forming galaxies redshifts near 0.3 with Hubble Space Telescope their continua (or Continuum, LyC). We find strong (6σ...
Abstract We present the spectroscopic confirmation of a protocluster at z = 7.88 behind galaxy cluster Abell 2744 (hereafter A2744-z7p9OD). Using JWST NIRSpec, we find seven galaxies within projected radius 60 kpc. Although reside in an overdensity around ≳20× greater than random volume, they do not show strong Ly α emission. place 2 σ upper limits on rest-frame equivalent width <16–28 Å. Based tight to emission, constrain volume-averaged neutral fraction hydrogen intergalactic medium be...
The escape fraction of Lyman-continuum (LyC) photons ($f_{esc}$) is a key parameter for determining the sources cosmic reionization at $z\geq 6$. At these redshifts, owing to opacity intergalactic medium, LyC emission cannot be measured directly. However, leakers during epoch could identified using indirect indicators that have been extensively tested low and intermediate redshifts. These include high [OIII]/[OII] flux ratio, star-formation surface density, compact sizes. In this work, we...
Abstract We present JWST/NIRSpec prism spectroscopy of MACS0647−JD, a triply lensed z ∼ 11 candidate discovered in Hubble Space Telescope imaging and spatially resolved by JWST into two components, A B. Spectroscopy component yields spectroscopic redshift = 10.17 based on seven detected emission lines: C iii ] λ 1907, 1909, [O ii 3727, [Ne 3869, 3968, H δ 4101, γ 4340, 4363. These are the second-most distant detections these lines to date, galaxy observed just 460 million years after Big...
Abstract The radial gradient of gas-phase metallicity is a powerful probe the chemical and structural evolution star-forming galaxies, closely tied to disk formation gas kinematics in early Universe. We present spatially resolved dynamical properties for sample 25 galaxies at 0.5 ≲ z 1.7 from MSA-3D survey. These innovative observations provide 3D spectroscopy spatial resolution approaching JWST’s diffraction limit high spectral R ≃ 2700. gradients measured our galaxy range −0.03 0.02 dex...
The WFC3 Infrared Spectroscopic Parallel Survey uses the Hubble Space Telescope (HST) infrared grism capabilities to obtain slitless spectra of thousands galaxies over a wide redshift range including peak star formation history universe. We select population very strong emission-line with rest-frame equivalent widths (EWs) higher than 200 Å. A total 176 objects are found 0.35 < z 2.3 in 180 arcmin2 area that we have analyzed so far. This consists young and low-mass starbursts high specific...
We study large-scale outflows in a sample of 96 star-forming galaxies at 1 ≲ z 2, using near-UV spectroscopy Fe ii and Mg absorption emission. The average blueshift the interstellar lines with respect to systemic velocity is −85 ± 10 km s−1 ∼ 1.5, standard deviation 87 s−1; this decrease factor two from measured for far-UV similarly selected 2. profiles λλ2796, 2803 show much more variety than profiles, which are always seen absorption; ranges strong emission pure absorption, common blue UV...
We present results from near-infrared spectroscopy of 26 emission-line galaxies at z ~ 2 obtained with the FIRE spectrometer on Magellan Baade telescope. The sample was selected WISP survey, which uses grism Hubble Space Telescope Wide Field Camera 3 to detect over 0.3 < 2.3. Our follow-up (R~5000) 1.0-2.5 micron permits detailed measurements physical properties z~2 galaxies. Dust-corrected star formation rates for range ~5-100 M_sun yr-1. derive a median metallicity ~0.45 Z_sun, and...
We give an overview of the Grism Lens Amplified Survey from Space (GLASS), a large Hubble Telescope program aimed at obtaining grism spectroscopy fields 10 massive clusters galaxies redshift z = 0.308–0.686, including Frontier Fields (HFF). The Wide Field Camera 3 (WFC3) yields near-infrared spectra cluster cores covering wavelength range 0.81–1.69 μm through grisms G102 and G141, while Advanced for Surveys in parallel mode provides G800L infall regions clusters. WFC3 are taken two almost...
Spectroscopic observations of Hα and Hβ emission lines 128 star-forming galaxies in the redshift range 0.75 ⩽ z 1.5 are presented. These data were taken with slitless spectroscopy using G102 G141 grisms Wide-Field-Camera 3 (WFC3) on board Hubble Space Telescope as part WFC3 Infrared Parallel survey. Interstellar dust extinction is measured from stacked spectra that cover Balmer decrement (Hα/Hβ). We present a function luminosity (down to × 1041 erg s−1), galaxy stellar mass (reaching 4 108...
The Grism Lens-Amplified Survey from Space (GLASS) is a Hubble Telescope (HST) Large Program, which will obtain 140 orbits of grism spectroscopy the core and infall regions 10 galaxy clusters, selected to be among very best cosmic telescopes. Extensive HST imaging available many sources including CLASH Frontier Fields programs. We introduce survey by analyzing spectra faint multiply-imaged galaxies $z\gtrsim6$ candidates obtained first seven out fourteen targeting cluster MACS0717.5+3745....
We present the first robust measurement of high redshift mass-metallicity (MZ) relation at 10^{8}< M/M_{\sun} < 10^{10}, obtained by stacking spectra 83 emission-line galaxies with secure redshifts between 1.3 z 2.3. For these redshifts, infrared grism spectroscopy Hubble Space Telescope Wide Field Camera 3 is sensitive to R23 metallicity diagnostic: ([OII]3726,3729 + [OIII] 4959,5007)/H\beta. Using stacked in four mass quartiles, we find a MZ that declines significantly decreasing mass,...
Early star-forming galaxies produced copious ionizing photons. A fraction of these photons escaped gas within to reionize the entire Universe. This escape is crucial for determining how Universe became reionized, but neutral intergalactic medium precludes direct measurement at high-redshifts. Indirect estimates must describe was reionized. Here, we present new Keck Cosmic Web Imager spatially-resolved spectroscopy resonant Mg II 2800 doublet from a redshift 0.36 galaxy, J1503+3644, with...
Far-ultraviolet (FUV; ~1200-2000 angstroms) spectra are fundamental to our understanding of star-forming galaxies, providing a unique window on massive stellar populations, chemical evolution, feedback processes, and reionization. The launch JWST will soon usher in new era, pushing the UV spectroscopic frontier higher redshifts than ever before, however, its success hinges comprehensive star populations gas conditions that power observed spectral features. This requires level detail is only...
Combining 66 ultraviolet (UV) spectra and ancillary data from the Low-Redshift Lyman Continuum Survey (LzLCS) 23 LyC observations by earlier studies, we form a statistical sample of star-forming galaxies at $z \sim 0.3$ to study role cold interstellar medium (ISM) gas in leakage ionizing radiation. We first constrain massive star content (ages metallicities) UV attenuation, fitting stellar continuum with combination simple population models. The models, together accurate flux measurements,...