A5083872295- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Advanced Optical Sensing Technologies
- Nuclear Physics and Applications
- Ocular and Laser Science Research
- Atomic and Subatomic Physics Research
- Astronomical Observations and Instrumentation
- Mycotoxins in Agriculture and Food
- Calibration and Measurement Techniques
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Photocathodes and Microchannel Plates
- Radiation Detection and Scintillator Technologies
- Astro and Planetary Science
- Optical Systems and Laser Technology
- Advanced Data Storage Technologies
Goddard Space Flight Center
2020-2024
University of America
2022-2023
Catholic University of America
2022-2023
University of Arizona
2015-2020
We discuss new Keck/MOSFIRE spectroscopic observations of four luminous galaxies at z ≃ 7–9 selected to have intense optical line emission by Roberts-Borsani et al. Previous follow-up has revealed Lyα in two the galaxies. Our MOSFIRE confirm that is present entire sample. detect galaxy COS-zs7-1, confirming its redshift as zLyα = 7.154, and we EGS-zs8-2 7.477, verifying an earlier tentative detection. The ubiquity this sample puzzling given IGM expected be significantly neutral over 7 < 9....
We present Keck/MOSFIRE observations of UV metal lines in four bright gravitationally-lensed z~6-8 galaxies behind the cluster Abell 1703. The spectrum A1703-zd6, a highly-magnified star forming galaxy with Lyman-alpha redshift z=7.045, reveals confident detection nebular CIV emission line (unresolved FWHM < 125 km/s). are not detected three other galaxies. At z~2-3, is observed just 1% UV-selected presence strong one small sample targeted this paper may indicate hard ionizing spectra more...
ABSTRACT Nearly a decade ago, we began to see indications that reionization-era galaxies power hard radiation fields rarely seen at lower redshift. Most striking were detections of nebular C iv emission in what appeared be typical low-mass galaxies, requiring an ample supply 48 eV photons triply ionize carbon. We have obtained deep JWST/NIRSpec R = 1000 spectroscopy the two z &gt; 6 iv-emitting known prior JWST. Here, present rest-UV optical spectrum one these systems, multiply-imaged...
Abstract JWST has recently discovered a subset of reionization era galaxies with ionized gas that is metal-poor in oxygen and carbon but heavily enriched nitrogen. This abundance pattern almost never seen lower-redshift commonly observed globular cluster stars. We have demonstrated this peculiar appears compact (≃20 pc) galaxy undergoing strong burst star formation. was originally selected based on C iv emission, indicating hard radiation field rarely locally. In paper, we present...
Nearby dwarf galaxies provide a unique laboratory in which to test stellar population models below $Z_\odot/2$. Such tests are particularly important for interpreting the surprising high-ionization UV line emission detected at $z>6$ recent years. We present HST/COS ultraviolet spectra of ten nearby metal-poor star-forming selected show He II SDSS optical spectra. The targets span nearly dex gas-phase oxygen abundance ($7.8<12+\log\mathrm{O/H}<8.5$) and uniformly large specific star formation...
Abstract We present the Magellan /FIRE detection of highly ionized C iv λ 1550 and O iii ] 1666 in a deep infrared spectrum z = 6.11 gravitationally lensed low-mass galaxy RXC J2248.7-4431-ID3, which has previously known Ly α . No corresponding emission is detected at expected location He ii 1640. The upper limit on , paired with constrains possible ionization scenarios. Production requires ionizing photons 2.5–3.5 Ryd, but once that state their multiplet powered by collisional excitation...
Abstract Massive foreground galaxy clusters magnify and distort the light of objects behind them, permitting a view into both extremely distant intrinsically faint populations. We present here candidate high-redshift galaxies from Reionization Lensing Cluster Survey (RELICS), Hubble Spitzer Space Telescope survey 41 massive spanning an area ≈200 arcmin 2 . These were selected to be excellent lenses, we find similar sample sizes magnitude distributions as And Supernova with (CLASH). discover...
MACS0647$-$JD is a triply-lensed $z\sim11$ galaxy originally discovered with the Hubble Space Telescope. Here we report new JWST imaging, which clearly resolves as having two components that are either merging galaxies or stellar complexes within single galaxy. Both very small, masses $\sim10^8\,M_\odot$ and radii $r<100\,\rm pc$. The brighter larger component "A" intrinsically blue ($\beta\sim-2.6$), likely due to recent star formation no dust, spatially extended an effective radius...
Recent studies have revealed intense UV metal emission lines in a modest sample of z>7 Lyman-alpha emitters, indicating hard ionizing spectrum is present. If such high ionization features are shown to be common, it may indicate that extreme radiation fields play role regulating the visibility reionization era. Here we present deep near-infrared spectra seven galaxies with at 5.4<z<8.7 (including newly-confirmed lensed galaxy z=6.031) and three bright photometric targets. In nine sources do...
Measurements of the galaxy UV luminosity function at z>6 suggest that young stars hosted in low-mass star-forming galaxies produced bulk hydrogen-ionizing photons necessary to reionize intergalactic medium (IGM) by redshift z~6. Whether dominated cosmic reionization, however, also depends on their stellar populations and interstellar properties, which set, among other things, production rate H-ionizing photons, $\xi_\text{ion}^\star$, fraction these escaping into IGM. Given difficulty...
The most distant galaxies known are at z~10-11, observed 400-500 Myr after the Big Bang. few z~10-11 candidates discovered to date have been exceptionally small- barely resolved, if all, by Hubble Space Telescope. Here we present discovery of SPT0615-JD, a fortuitous z~10 (z_phot=9.9+/-0.6) galaxy candidate stretched into an arc over ~2.5" effects strong gravitational lensing. Discovered in Reionization Lensing Cluster Survey (RELICS) Treasury program and companion S-RELICS Spitzer program,...
Abstract Extreme, young stellar populations are considered to be the primary contributor cosmic reionization. How Lyman continuum (LyC) escapes these galaxies remains highly elusive, and it is challenging observe this process in actual LyC emitters without resolving relevant physical scales. We investigate Sunburst Arc, a strongly lensed emitter at z = 2.37 that reveals an exceptionally small-scale (tens of parsecs) region high escape. The small (<100 pc) LyC-leaking has extreme...
The ubiquity of Lyman alpha (Ly$\alpha$) emission in a sample four bright [O III]-strong star-forming galaxies with redshifts above 7 has led to the suggestion that such luminous sources represent distinct population compared their fainter, more numerous, counterparts. presence Ly$\alpha$ within reionization era could indicate these created early ionized bubbles due unusually strong radiation, possibly active galactic nuclei. To test this hypothesis we have secured long integration spectra...
Abstract Large surveys of galaxy clusters with the Hubble Space Telescope ( HST ) and Spitzer , including Cluster Lensing And Supernova survey Frontier Fields, have demonstrated power strong gravitational lensing to efficiently deliver large samples high-redshift galaxies. We extend this strategy through a wider, shallower named RELICS, Reionization Survey, described here. Our 188-orbit Treasury Program observed 41 at 0.182 ≤ z 0.972 Advanced Camera for Surveys (ACS) WFC3/IR imaging spanning...
Abstract Strong gravitational lensing by clusters of galaxies probes the mass distribution at core each cluster and magnifies universe behind it. MACS J0417.5−1154 z = 0.443 is one most massive known based on weak lensing, X-ray, Sunyaev–Zel’dovich analyses. Here we compute a strong lens model J0417 Hubble Space Telescope imaging observations collected, in part, Reionization Lensing Cluster Survey (RELICS), recently reported spectroscopic redshifts from MUSE instrument Very Large (VLT). We...
We analyze spectra of a gravitationally lensed galaxy, known as the Sunburst Arc, that is leaking ionizing photons, also Lyman continuum (LyC). Magnification from gravitational lensing permits galaxy to be spatially resolved into one region leaks and several do not. Rest-frame ultraviolet optical Magellan target ten different regions along including six multiple images LyC region, well four not show emission. The rest-frame photon emitting reveal blue-shifted ($\Delta V$=27 km s$^{-1}$)...
Strong gravitational lensing by galaxy clusters magnifies background galaxies, enhancing our ability to discover statistically significant samples of galaxies at z>6, in order constrain the high-redshift luminosity functions. Here, we present first five lens models out Reionization Lensing Cluster Survey (RELICS) Hubble Treasury Program, based on new HST WFC3/IR and ACS imaging RXC J0142.9+4438, Abell 2537, 2163, J2211.7-0349, ACT-CLJ0102-49151. The derived magnification is essential for...
Abstract We present a strong-lensing analysis of the cluster PSZ1 G311.65−18.48, based on Hubble Space Telescope imaging, archival VLT/MUSE spectroscopy, and Chandra X-ray data. This cool-core ( z = 0.443) lenses brightest lensed galaxy known, dubbed “Sunburst Arc” 2.3703), Lyman continuum (LyC) emitting multiply imaged 12 times. identify in this field 14 additional strongly galaxies to constrain strong-lens model report secure spectroscopic redshifts four them. measure projected core mass M...
Abstract We present a strong lensing analysis of four massive galaxy clusters imaged with the Hubble Space Telescope in Reionization Lensing Cluster Survey. use light-traces-mass technique to uncover sets multiple images and constrain mass distribution clusters. These models are first published for Abell S295 MACS J0159.8-0849 improvements over previous 697 J0025.4-1222. Our J0025.4-1222 shows bimodal supporting merger scenarios proposed these The updated model suggests substantially smaller...
Abstract Strong gravitational lensing by galaxy clusters has become a powerful tool for probing the high-redshift universe, magnifying distant and faint background galaxies. Reliable strong-lensing (SL) models are crucial determining intrinsic properties of distant, magnified sources constructing their luminosity function. We present here first SL analysis MACS J0308.9+2645 PLCK G171.9−40.7, two massive imaged with Hubble Space Telescope , in framework Reionization Lensing Cluster Survey...
Recent observations have revealed the presence of strong CIII] emission (EW$_{\rm{CIII]}}>20$ Å) in $z>6$ galaxies, origin which remains unclear. In an effort to understand nature these line emitters, we initiated a survey targeting gravitationally-lensed reionization era analogs identified HST imaging clusters from RELICS survey. Here report initial results on four galaxies selected low stellar masses (2-8$\times$10$^7$ M$_\odot$) and J$_{125}$-band flux excesses indicative intense...
Nearly a decade ago, we began to see indications that reionization-era galaxies power hard radiation fields rarely seen at lower redshift. Most striking were detections of nebular CIV emission in what appeared be typical low mass galaxies, requiring an ample supply 48 eV photons triply ionize carbon. The nature this population has long remained unclear owing limitations ground-based spectroscopy. We have obtained deep JWST/NIRSpec R=1000 spectroscopy the two z>6 CIV-emitting known prior...
Extensive surveys with the \textit{Hubble Space Telescope} (HST) over past decade, targeting some of most massive clusters in sky, have uncovered dozens galaxy-cluster strong lenses. The cluster strong-lens scale is typically $θ_{E}\sim10\arcsec$ to $\sim30-35\arcsec$, only a handful known Einstein radii $θ_{E}\sim40\arcsec$ or above (for $z_{source}=2$, nominally). Here we report another very large lens, RXC J0032.1+1808 ($z=0.3956$), second richest redMapper catalog and 85th Planck...
Abstract Strong gravitational lensing (SL) is a powerful means of mapping the distribution dark matter. In this work, we perform an SL analysis prominent X-ray cluster RXJ0152.7-1357 ( z = 0.83, also known as CL0152.7-1357) in Hubble Space Telescope images, taken framework Reionization Lensing Cluster Survey (RELICS). On top previously 3.93 galaxy multiply imaged by RXJ0152.7-1357, for which identify additional multiple image, guided light-traces-mass approach, seven new sets background...
We present new observations of sixteen bright ($r=19-21$) gravitationally lensed galaxies at $z\simeq 1-3$ selected from the CASSOWARY survey. Included in our sample is $z=1.42$ galaxy CSWA-141, one brightest known reionization-era analogs high redshift (g=20.5), with a large sSFR (31.2 Gyr$^{-1}$) and an [OIII]+H$\beta$ equivalent width (EW$_{\rm{[OIII]+H\beta}}$=730~\r{A}) that nearly identical to average value expected 7-8$. In this paper, we investigate rest-frame UV nebular line...