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Publications (441)
GJ 1214b is the archetype sub-Neptune for which thick aerosols have prevented us from constraining its atmospheric properties for over a decade. In this study, we leverage the panchromatic transmission spectrum of GJ 1214b established by the Hubble Space Telescope (HST) and JWST to investigate its atmospheric properties using a suite of atmospheric...
The morphology of a galaxy reflects the mix of physical processes occurring within and around it, offering indirect clues to its formation and evolution. We apply both visual classification and computer vision to test the suspected connection between galaxy mergers and active galactic nucleus (AGN) activity, as evidenced by a close/merging galaxy p...
We present the robust selection of high-redshift quiescent galaxies (QG) and poststarburst (PSB) galaxies using ultra-deep NIRCam and MIRI imaging from the JWST Advanced Deep Extragalactic Survey (JADES). At 3 < z < 6, MIRI 7.7 μ m imaging provides rest-frame J band, which is commonly used to break the degeneracy between old stellar populations and...
The topology of reionization and the environments where galaxies efficiently produce ionizing photons are key open questions. For the first time, we investigate the correlation between ionizing photon production efficiency, $\xi_{\rm ion}$, and galaxy overdensity, $\log(1+\delta)$. We analyze the ionizing properties of 93 galaxies between $0.7 < z...
Sub-Neptune planets with radii smaller than Neptune (3.9 R ⊕ ) are the most common type of planet known to exist in the Milky Way, even though they are absent in the solar system. These planets can potentially have a large diversity of compositions as a result of different mixtures of rocky material, icy material, and gas accreted from a protoplane...
Sub-Neptune planets with radii smaller than Neptune (3.9 Re) are the most common type of planet known to exist in The Milky Way, even though they are absent in the Solar System. These planets can potentially have a large diversity of compositions as a result of different mixtures of rocky material, icy material and gas accreted from a protoplanetar...
GJ1214b is the archetype sub-Neptune for which thick aerosols have prevented us from constraining its atmospheric properties for over a decade. In this study, we leverage the panchromatic transmission spectrum of GJ1214b established by HST and JWST to investigate its atmospheric properties using a suite of atmospheric radiative transfer, photochemi...
For the first time, we systematically search for galaxies with extended emission line and potential outflows features using medium-band images in the GOODS-S field by comparing the morphology in medium-band images to adjacent continuum and UV bands. We look for galaxies that have a maximum extent 50\% larger, an excess area 30\% greater, or an axis...
The JWST Advanced Deep Extragalactic Survey (JADES) is a multi-cycle JWST program that has taken among the deepest near-infrared images to date (down to $\sim$30.5 ABmag) over $\sim$25 arcmin$^2$ in the GOODS-S field in two sets of observations with one year of separation. This presented the first opportunity to systematically search for transients...
Using deep JWST imaging from JADES, JEMS, and SMILES, we characterize optically faint and extremely red galaxies at z > 3 that were previously missing from galaxy census estimates. The data indicate the existence of abundant, dusty, and poststarburst-like galaxies down to 10 ⁸ M ⊙ , below the sensitivity limit of Spitzer and the Atacama Large Milli...
Observations of debris disks offer important insights into the formation and evolution of planetary systems. Though M dwarfs make up approximately 80% of nearby stars, very few M dwarf debris disks have been studied in detail—making it unclear how or if the information gleaned from studying debris disks around more massive stars extends to the more...
We report the discovery of an extreme galaxy overdensity at z = 5.4 in the GOODS-S field using James Webb Space Telescope (JWST)/NIRCam imaging from JADES and JEMS alongside JWST/NIRCam wide-field slitless spectroscopy from FRESCO. We identified potential members of the overdensity using Hubble Space Telescope+JWST photometry spanning λ = 0.4–5.0 μ...
The isolated globule B335 contains a single, low-luminosity Class 0 protostar associated with a bipolar nebula and outflow system seen nearly perpendicular to its axis. We observed the innermost regions of this outflow as part of JWST/NIRCam Guaranteed Time Observations program 1187, primarily intended for wide-field slitless spectroscopy of backgr...
HDF850.1 is the brightest submillimeter galaxy (SMG) in the Hubble Deep Field. It is known as a heavily dust-obscured star-forming galaxy embedded in an overdense environment at z = 5.18. With nine-band NIRCam images at 0.8–5.0 μ m obtained through the JWST Advanced Deep Extragalactic Survey, we detect and resolve the rest-frame UV–optical counterp...
We report observations with the JWST/NIRCam coronagraph of the Fomalhaut ( α PsA) system. This nearby A star hosts a complex debris disk system discovered by the IRAS satellite. Observations in F444W and F356W filters using the round 430R mask achieve a contrast ratio of ∼4 × 10 ⁻⁷ at 1″ and ∼4 × 10 ⁻⁸ outside of 3″. These observations reach a sens...
The abundances of main carbon- and oxygen-bearing gases in the atmospheres of giant exoplanets provide insights into atmospheric chemistry and planet formation processes1,2. Thermochemistry suggests that methane (CH4) should be the dominant carbon-bearing species below about 1,000 K over a range of plausible atmospheric compositions³; this is the c...
We present near-infrared (NIR) ground-based Y , J , H , and K imaging obtained in the James Webb Space Telescope (JWST) North Ecliptic Pole Time Domain Field (NEP TDF) using the MMT-Magellan Infrared Imager and Spectrometer on the MMT. These new observations cover a field of approximately 230 arcmin ² in Y , H , and K, and 313 arcmin ² in J . Using...
We present JWST Extragalactic Medium-band Survey, the first public medium-band imaging survey carried out using JWST/NIRCam and NIRISS. These observations use ∼2 and ∼4 μ m medium-band filters (NIRCam F182M, F210M, F430M, F460M, F480M; and NIRISS F430M and F480M in parallel) over 15.6 arcmin ² in the Hubble Ultra Deep Field (UDF), thereby building...
HDF850.1 is the brightest submillimeter galaxy (SMG) in the Hubble Deep Field. It is known as a heavily dust-obscured star-forming galaxy embedded in an overdense environment at $z = 5.18$. With nine-band NIRCam images at 0.8-5.0 $\mu$m obtained through the JWST Advanced Deep Extragalactic Survey (JADES), we detect and resolve the rest-frame UV-opt...
The abundances of major carbon and oxygen bearing gases in the atmospheres of giant exoplanets provide insights into atmospheric chemistry and planet formation processes. Thermochemistry suggests that methane should be the dominant carbon-bearing species below $\sim$1000 K over a range of plausible atmospheric compositions; this is the case for the...
High-contrast imaging of debris disk systems permits us to assess the composition and size distribution of circumstellar dust, to probe recent dynamical histories, and to directly detect and characterize embedded exoplanets. Observations of these systems in the infrared beyond 2--3 $\mu$m promise access to both extremely favorable planet contrasts...
The Y-dwarf WISE 1828+2650 is one of the coldest known Brown Dwarfs with an effective temperature of $\sim$300 K. Located at a distance of just 10 pc, previous model-based estimates suggest WISE1828+2650 has a mass of $\sim$5-10 Mj, making it a valuable laboratory for understanding the formation, evolution and physical characteristics of gas giant...
We report the discovery of an extreme galaxy overdensity at $z = 5.4$ in the GOODS-S field using JWST/NIRCam imaging from JADES and JEMS alongside JWST/NIRCam wide field slitless spectroscopy from FRESCO. We identified potential members of the overdensity using HST+JWST photometry spanning $\lambda = 0.4-5.0\ \mu\mathrm{m}$. These data provide accu...
The Near Infrared Camera for the James Webb Space Telescope (JWST) is delivering the imagery that astronomers have hoped for ever since JWST was proposed back in the 1990s. In the Commissioning Period that extended from right after launch to early 2022 July, NIRCam has been subjected to a number of performance tests and operational checks. The came...
We present JEMS (JWST Extragalactic Medium-band Survey), the first public medium-band imaging survey carried out using JWST/NIRCam and NIRISS. These observations use $\sim2\mu$m and $\sim4\mu$m medium-band filters (NIRCam F182M, F210M, F430M, F460M, F480M; and NIRISS F430M & F480M in parallel) over 15.6 square arcminutes in the Hubble Ultra Deep Fi...
The dramatic first images with JWST demonstrated its power to provide unprecedented spatial detail for galaxies in the high-redshift universe. Here, we leverage the resolution and depth of the JWST Cosmic Evolution Early Release Science Survey data in the Extended Groth Strip to perform pixel-level morphological classifications of galaxies in JWST...
The Near Infrared Camera for the James Webb Space Telescope is delivering the imagery that astronomers have hoped for ever since JWST was proposed back in the 1990s. In the Commissioning Period that extended from right after launch to early July 2022 NIRCam has been subjected to a number of performance tests and operational checks. The camera is ex...
Surveys with James Webb Space Telescope (JWST) have discovered candidate galaxies in the first 400 Myr of cosmic time. The properties of these distant galaxies provide initial conditions for understanding early galaxy formation and cosmic reionisation. Preliminary indications have suggested these candidate galaxies may be more massive and abundant...
The dramatic first images with James Webb Space Telescope (JWST) demonstrated its power to provide unprecedented spatial detail for galaxies in the high-redshift universe. Here, we leverage the resolution and depth of the JWST Cosmic Evolution Early Release Science Survey (CEERS) data in the Extended Groth Strip (EGS) to perform pixel-level morphol...
JWST observations of high redshift galaxies are used to measure their star formation histories -- the buildup of stellar mass in the earliest galaxies. A novel analysis program, SEDz*, compares near-IR spectral energy distributions for galaxies with redshift $5<z<7$ to combinations of stellar population templates evolved from $z=12$. We exploit NIR...
Judith Pipher, who passed away on 21 February 2022, was a pioneer in the field of infrared astronomy and a role model, teacher, advisor and more.
We present a spectroscopic and photometric analysis of a sample of 416,288 galaxies from the Sloan Digital Sky Survey (SDSS) matched to mid-infrared (mid-IR) data from the Wide-Field Infrared Survey Explorer (WISE). By using a new spectroscopic fitting package, GELATO (Galaxy/AGN Emission Line Analysis TOol), we are able to retrieve emission line f...
The Near Infrared Camera (NIRCam) instrument on the upcoming James Webb Space Telescope will offer an unprecedented view of the most distant galaxies. In preparation for future deep NIRCam extragalactic surveys, it is crucial to understand the color selection of high-redshift galaxies using the Lyman dropout technique. To that end, we have used the...
Galaxy clustering measurements can be used to constrain many aspects of galaxy evolution, including galaxy host halo masses, satellite quenching efficiencies, and merger rates. We simulate JWST galaxy clustering measurements at z ∼ 4–10 by utilizing mock galaxy samples produced by an empirical model, the universemachine. We also adopt the survey fo...
The NIRCam instrument on the upcoming James Webb Space Telescope (JWST) will offer an unprecedented view of the most distant galaxies. In preparation for future deep NIRCam extragalactic surveys, it is crucial to understand the color selection of high-redshift galaxies using the Lyman dropout technique. To that end, we have used the JAdes extraGala...
Half of the energy emitted by late-T- and Y-type brown dwarfs emerges at 3.5 ≤ λ μ m ≤ 5.5. We present new L ′ (3.43 ≤ λ μ m ≤ 4.11) photometry obtained at the Gemini North telescope for nine late-T and Y dwarfs, and synthesize L ′ from spectra for an additional two dwarfs. The targets include two binary systems that were imaged at a resolution of...
Half of the energy emitted by late-T- and Y-type brown dwarfs emerges at 3.5 < lambda um < 5.5. We present new L' (3.43 < lambda um < 4.11) photometry obtained at the Gemini North telescope for nine late-T and Y dwarfs, and synthesize L' from spectra for an additional two dwarfs. The targets include two binary systems which were imaged at a resolut...
Galaxy clustering measurements can be used to constrain many aspects of galaxy evolution, including galaxy host halo masses, satellite quenching efficiencies, and merger rates. We simulate JWST galaxy clustering measurements at z$\sim$4$-$10 by utilizing mock galaxy samples produced by an empirical model, the UniverseMachine. We also adopt the surv...
The JWST Advanced Deep Extragalactic Survey (JADES) is a joint program of the JWST NIRCam and NIRSpec Guaranteed Time Observation (GTO) teams involving over 800 hours of observation. This paper describes the imaging portion of the program which covers nearly 200 square arc minutes divided between two well-studied fields with excellent supporting da...
We describe the design and performance of the near-infrared (1.51–1.70 μm), fiber-fed, multi-object (300 fibers), high resolution (R = λ/Δλ ~ 22,500) spectrograph built for the Apache Point Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey of ~10⁵ red giant stars that systematically sampled all Milky Way populations (bulge, dis...
We describe the design and performance of the near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrograph built for the Apache Point Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey of ~ 10^5 red giant stars that systematically sampled all Milky Way p...
We present an original phenomenological model to describe the evolution of galaxy number counts, morphologies, and spectral energy distributions across a wide range of redshifts (0.2<z<15) and stellar masses [Log10 M/Msun >6]. Our model follows observed mass and luminosity functions of both star-forming and quiescent galaxies, and reproduces the re...
We present an original phenomenological model to describe the evolution of galaxy number counts, morphologies, and spectral energy distributions across a wide range of redshifts ($0.2<z<15$) and stellar masses [$\log(\mathrm{M}/\mathrm{M}_{\odot})\ge6$]. Our model follows observed mass and luminosity functions of both star-forming and quiescent gal...
Imaging in the infrared (2.2μ) minimizes the impact of dust obscuration and allows reliable mapping of the mass-tracing stellar population in spiral galaxies. We find dramatic differences compared to photometry at shorter wavelengths (e.g. 0.8μ). As an example, the observations of the mini-bar and inner spiral arms of M 51 are discussed.
A study of the Galactic Center stellar population is continuing with a sensitive 2 μ m CCD camera. Using a 64 × 64 detector array, background limited images are recorded with modest amounts of observing time (t obs ≈ 20 sec to reach K=13). Magnitudes have been extracted using DAOPHOT from repeated imaging of the central 5′ × 5′ to search among appr...
Using unprecedented sensitivity and angular resolution, the Mid-IR (MIRI) instrument for the James WebbSpace Telescope (JWST) will provide imaging, coronagraphy, single slit and integral- eld spectroscopy for manyscience observations. The expectation is that the operational design of the JWST will include parallel modes.We have been studying the in...
The 6 billion solar mass supermassive black hole at the center of the giant
elliptical galaxy M87 powers a relativistic jet. Observations at millimeter
wavelengths with the Event Horizon Telescope have localized the emission from
the base of this jet to angular scales comparable to the putative black hole
horizon. The jet might be powered directly...
We present multiple epochs of near-infrared spectroscopy for a sample of 25 young stars, including T Tauri, Herbig Ae/Be,
and FU Ori objects. Using the FSPEC instrument on the Bok 90-inch telescope, we obtained K-band spectra of the Brγ transition of hydrogen, with a resolution of ≈3500. Epochs were taken over a span of >1 yr, sampling
time-spacing...
We use the Spitzer Infrared Spectrograph (IRS) to study four infalling
cluster galaxies with signatures of on-going ram-pressure stripping. H$_2$
emission is detected in all four; two show extraplanar H$_2$ emission. The
emission usually has a warm (T $\sim$ $115 - 160$K) and a hot (T $\sim$ 400 $-$
600K) component that is approximately two orders...
We present near-IR spectra of a sample of T Tauri, Herbig Ae/Be, and FU Ori
objects. Using the FSPEC instrument on the Bok 90-inch telescope, we obtained
K-band spectra with a resolution of ~3500. Here we present spectra of the
v=2->0 and v=3->1 bandheads of ro-vibrational transitions of carbon monoxide.
We observed these spectra over multiple epoc...
We present the results of a Spitzer and Herschel study of a select group
of nearby cluster galaxies where we observe the effects of ram-pressure
on the molecular and dust components of these galaxies. In a few cases,
we see evidence for molecular gas and dust emission outside of the
galaxy, which is most likely caused by ram-pressure stripping. Mor...
We measure the clustering of extremely red objects (EROs) in ≈8 deg2 of the NOAO Deep Wide Field Survey Boötes field in order to establish robust links between ERO (z ≈ 1.2) and local galaxy (z < 0.1) populations. Three different color selection criteria from the literature are analyzed to assess the consequences of using different criteria for sel...
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) uses a dedicated 300-fiber, narrow-band near-infrared (1.51-1.7 mu m), high resolution (R similar to 22,500) spectrograph to survey approximately 100,000 giant stars across the Milky Way. This three-year survey, in operation since late-summer 2011 as part of the Sloan Digital Sky S...
The Near-Infrared Camera (NIRCam) on the James Webb Space Telescope
(JWST) offers revolutionary gains in sensitivity throughout the 1-5
μm region. NIRCam will enable great advances in all areas of
astrophysics, from the composition of objects in our own Kuiper Belt and
the physical properties of planets orbiting nearby stars to the
formation of sta...
The James Webb Space Telescope (JWST) is the successor to the Hubble Space Telescope. JWST will be an infrared-optimized telescope, with an approximately 6.5 m diameter primary mirror, that is located at the Sun-Earth L2 Lagrange point. Three of JWST’s four science instruments use Teledyne HgCdTe HAWAII-2RG (H2RG) near infrared detector arrays. Dur...
We present the analysis of Herschel Spectral and Photometric Imaging Receiver far-infrared (FIR) observations of the z = 2.515 lensed galaxy SMM J163554.2+661225. Combining new 250, 350, and 500 μm observations with existing data, we make an improved fit to the FIR spectral energy distribution of this galaxy. We find a total infrared (IR) luminosit...
The NIRCam instrument on the James Webb Space Telescope (JWST) will provide a coronagraphic imaging capability to search for extrasolar planets in the 2 - 5 microns wavelength range. This capability is realized by a set of Lyot pupil stops with patterns matching the occulting mask located in the JWST intermediate focal plane in the NIRCam optical s...
The NIRCam instrument on the James Webb Space Telescope (JWST) will provide a coronagraphic imaging capability to search for extrasolar planets in the 2 – 5 microns wavelength range. This capability is realized by a set of Lyot pupil stops with patterns matching the occulting mask located in the JWST intermediate focal plane in the NIRCam optical s...
Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. In keeping with SDSS tradition, SDSS-III will provide reg...
The Near Infrared Camera (NIRCam) is one of the four science instruments of the James Webb Space Telescope (JWST). Its high sensitivity, high spatial resolution images over the 0.6 - 5 μm wavelength region will be essential for making significant findings in many science areas as well as for aligning the JWST primary mirror segments and telescope....
We present the 24 micron rest-frame luminosity function (LF) of star-forming
galaxies in the redshift range 0.0 < z < 0.6 constructed from 4047
spectroscopic redshifts from the AGN and Galaxy Evolution Survey of 24 micron
selected sources in the Bootes field of the NOAO Deep Wide-Field Survey. This
sample provides the best available combination of...
We report the discovery of a galaxy cluster at z = 1.62 located in the Spitzer Wide-Area Infrared Extragalactic survey XMM-LSS field. This structure was selected solely as an overdensity of galaxies with red Spitzer/Infrared Array Camera colors, satisfying ([3.6] - [4.5])AB> - 0.1mag. Photometric redshifts derived from the Subaru XMM Deep Survey (B...
The Advanced Camera for Surveys and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) have been used to obtain new Hubble Space Telescope images of NGC 4038/4039 ("The Antennae"). These new observations allow us to better differentiate compact star clusters from individual stars, based on both size and color. We use this ability to ex...
The ACS and NICMOS have been used to obtain new HST images of NGC 4038/4039 ("The Antennae"). These new observations allow us to better differentiate compact star clusters from individual stars, based on both size and color. We use this ability to extend the cluster luminosity function by approximately two magnitudes over our previous WFPC2 results...
High-contrast imaging can find and characterize gas giant planets around nearby young stars and the closest M stars, complementing radial velocity and astrometric searches by exploring orbital separations inaccessible to indirect methods. Ground-based coronagraphs are already probing within 25AU of nearby young stars to find objects as small as 3M{...
High-contrast imaging can find and characterize gas giant planets around
nearby young stars and the closest M stars, complementing radial
velocity and astrometric searches by exploring orbital separations
inaccessible to indirect methods. Ground-based coronagraphs are already
probing within 25 AU of nearby young stars to find objects as small as ....
High contrast imaging can find and characterize gas giant planets around nearby young stars and the closest M stars, complementing radial velocity and astrometric searches by exploring orbital separations inaccessible to indirect methods. Ground-based coronagraphs are already probing within 25 AU of nearby young stars to find objects as small as ~...
We present two different studies that shed light on the crucial interplay between the intracluster medium (ICM) and the stellar content of clusters. Our first study tested the impact of the stellar content of galaxy clusters on the enrichment of the ICM by carrying out XMM X-ray measurements of iron (Fe) content of 10 nearby galaxy clusters with me...
We have discovered a remarkable warm (130-160 K) molecular hydrogen tail with a H_2 mass of approximately 4*10^7 solar masses extending 20 kpc from a cluster spiral galaxy, ESO 137-001, in Abell 3627. At least half of this gas is lost permanently to the intracluster medium, as the tail extends beyond the tidal radius of the galaxy. We also detect a...