Susan A. Kassin
A5046154805- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Remote Sensing in Agriculture
- Geophysics and Gravity Measurements
- Cosmology and Gravitation Theories
- Scientific Research and Discoveries
- Career Development and Diversity
- History and Developments in Astronomy
- Solar and Space Plasma Dynamics
- CCD and CMOS Imaging Sensors
- Computational Physics and Python Applications
- Scientific Computing and Data Management
- Advanced Image Processing Techniques
- Advanced Vision and Imaging
- Plant Water Relations and Carbon Dynamics
- Assistive Technology in Communication and Mobility
- vaccines and immunoinformatics approaches
Space Telescope Science Institute
2014-2024
Johns Hopkins University
2018-2023
Laboratoire d’Astrophysique de Marseille
2022
Durham University
2020
UK Astronomy Technology Centre
2020
Goddard Space Flight Center
2011-2013
Deleted Institution
2012-2013
California Institute of Technology
2013
Associated Universities, Inc.
2012
Oak Ridge Associated Universities
2012
We analyze star formation (SF) as a function of stellar mass (M*) and redshift z in the All-Wavelength Extended Groth Strip International Survey. For 2905 field galaxies, complete to 1010(1010.8) M☉ at < 0.7(1), with Keck spectroscopic redshifts out = 1.1, we compile SF rates (SFRs) from emission lines, GALEX, Spitzer MIPS 24 μm photometry, optical-NIR M* measurements, HST morphologies. Galaxies reliable signs form distinct "main sequence" (MS), limited range SFRs given (1 σ ≲ ±0.3 dex),...
The DEEP2 and COMBO-17 surveys are used to study the evolution of luminosity function red blue galaxies $z \sim 1$. Schechter fits show that, since = 1$, $M^*_B$ dims by $\sim$ 1.3 mag per unit redshift for both color classes, $ϕ^*$ shows little change, while has formally nearly quadrupled. At face value, number density remained roughly constant $ z whereas that been rising. Luminosity densities support conclusions, but we note most red-galaxy occurs between our data local in highest bin,...
A large-scale hydrodynamical cosmological simulation, Horizon-AGN, is used to investigate the alignment between spin of galaxies and cosmic filaments above redshift 1.2. The analysis more than 150 000 per time step in range 1.2 < z 1.8 with morphological diversity shows that low-mass blue preferentially aligned their neighbouring filaments, while high-mass red tend have a perpendicular spin. reorientation massive provided by galaxy mergers, which are significant mass build-up. We find...
We describe the design and data sample from DEEP2 Galaxy Redshift Survey, densest largest precision-redshift survey of galaxies at z ~ 1 completed to date. The has conducted a comprehensive census massive galaxies, their properties, environments, large-scale structure down absolute magnitude M_B = -20 via ~90 nights observation on DEIMOS spectrograph Keck Observatory. covers an area 2.8 deg^2 divided into four separate fields, observed limiting apparent R_AB=24.1. Objects with < 0.7 are...
In this the first of a series Letters, we present panchromatic data set in Extended Groth Strip region sky. Our survey, All-Wavelength International Survey (AEGIS), aims to study physical properties and evolutionary processes galaxies at z ~ 1. It includes following deep, wide-field imaging sets: Chandra/ACIS X-ray, GALEX ultraviolet, CFHT/MegaCam Legacy optical, CFHT/CFH12K Hubble Space Telescope/ACS optical NICMOS near-infrared, Palomar/WIRC Spitzer/IRAC mid-infrared, Spitzer/MIPS...
The evolution of the B-band galaxy luminosity function is measured using a sample more than 11,000 galaxies with spectroscopic redshifts from DEEP2 Redshift Survey. rest-frame M_B versus U-B color-magnitude diagram shows that bi-modality seen in locally still present at z > 1. Dividing trough this color bimodality into predominantly red and blue galaxies, we find each type evolves differently. Blue counts tend to shift brighter magnitudes constant number density, while remain largely...
We report the discovery of a candidate galaxy with photo-z z~12 in first epoch JWST Cosmic Evolution Early Release Science (CEERS) Survey. Following conservative selection criteria we identify source robust z_phot = 11.8^+0.3_-0.2 (1-sigma uncertainty) m_F200W=27.3, and >7-sigma detections five filters. The is not detected at lambda < 1.4um deep imaging from both HST JWST, has faint ~3-sigma F150W F160W, which signal Ly-alpha break near red edge filters, implying z~12. This object (Maisie's...
Although giant clumps of stars are thought to be crucial galaxy formation and evolution, the most basic demographics still uncertain, mainly because definition has not been thoroughly discussed. In this paper, we carry out a study in star-forming galaxies at 0.5 < z 3, using our proposed physical that UV-bright discrete regions individually contribute more than 8% rest-frame UV light their galaxies. Clumps defined way significantly brighter H ii nearby large spiral galaxies, either or...
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...
Lyman Break Galaxy (LBG) candidates at z>10 are rapidly being identified in JWST/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources expected drop out bluer filters while well detected redder filters. However, here we show that dust-enshrouded star-forming galaxies lower redshifts (z<7) may also mimic near-infrared (near-IR) colors LBGs, representing potential contaminants LBG candidate samples. First, analyze...
Abstract The study of galaxy evolution hinges on our ability to interpret multiwavelength observations in terms their physical properties. To do this, we rely spectral energy distribution (SED) models, which allow us infer parameters from spectrophotometric data. In recent years, thanks wide and deep multiwave band surveys, the volume high-quality data have significantly increased. Alongside increased data, algorithms performing SED fitting improved, including better modeling prescriptions,...
Abstract In 2022 November, the James Webb Space Telescope (JWST) returned deep near-infrared images of A2744—a powerful lensing cluster capable magnifying distant, incipient galaxies beyond it. Together with existing Hubble (HST) imaging, this publicly available data set opens a fundamentally new discovery space to understand remaining mysteries formation and evolution across cosmic time. work, we detect measure some 60,000 objects 49 arcmin 2 JWST footprint down 5 σ limiting magnitude ∼30...
Abstract In this paper we describe the survey design for Ultradeep NIRSpec and NIRCam Observations before Epoch of Reionization (UNCOVER) Cycle 1 JWST Treasury program, which executed its early imaging component in 2022 November. The UNCOVER includes ultradeep (∼29–30AB) ∼45 arcmin 2 on around well-studied A2744 galaxy cluster at z = 0.308 will follow up ∼500 galaxies with extremely deep low-resolution spectroscopy NIRSpec/PRISM during summer 2023, repeat visits 2024. We science goals,...
We combine newly measured rotation velocities, velocity dispersions, and stellar masses to construct mass Tully-Fisher relations (M*TFRs) for 544 galaxies with strong emission lines at 0.1<z<1.2 from the All Wavelength Extended Groth Strip International Survey (AEGIS) Deep Extragalactic Evolutionary Probe 2 (DEEP2). The conventional M*TFR using only (Vrot) shows large scatter (~1.5 dex in velocity). residuals are correlated morphology sense that disturbed, compact, major merger have lower...
We present kinematic measurements of a large sample galaxies from the TKRS Survey in GOODS-N field. measure line-of-sight velocity dispersions integrated emission for 1089 with median z=0.637, and spatially resolved kinematics subsample 380 galaxies. This is largest to z ~ 1 date, allows us properties without morphological pre-selection. Emission linewidths provide bulk blue To fit kinematics, we models both rotation amplitude dispersion. Integrated linewidth correlates well combination...
The shutdown of star formation in galaxies is generally termed "quenching." Quenching may occur through a variety processes, e.g., active galactic nucleus (AGN) feedback, stellar or the shock heating gas dark matter halo. However, which mechanism(s) is, fact, responsible for quenching still question. This paper addresses by searching traces possible processes their effects on galaxy structural parameters such as mass (M*), M*/re, surface density (∼M*/r2e), and Sérsic index (n). We analyze...
We determine the intrinsic, 3-dimensional shape distribution of star-forming galaxies at 0<z<2.5, as inferred from their observed projected axis ratios. In present-day universe all masses 1e9 - 1e11 Msol are predominantly thin, nearly oblate disks, in line with previous studies. now extend this to higher redshifts, and find that among massive (M* > 1e10 Msol) disks most common geometric z < 2. Lower-mass z>1 possess a broad range shapes: fraction elongated (prolate) increases toward...
We study the evolution of scaling relations between maximum circular velocity, stellar mass and optical half-light radius star-forming disk-dominated galaxies in context LCDM-based galaxy formation models. Using data from literature combined with new DEEP2 AEGIS surveys we show that there is a consistent observational theoretical picture for these z\sim 2 to z=0. The observed weaker than virial dark matter haloes, which can be reproduced, both qualitatively quantitatively, simple,...
We present evidence from a sample of 544 galaxies the DEEP2 Survey for evolution internal kinematics blue with stellar masses ranging 8.0 < log M* (M_Sun) 10.7 over 0.2<z<1.2. provides galaxy spectra and Hubble imaging which we measure emission-line inclinations, respectively. Our large allows us to overcome scatter intrinsic properties in order examine trends kinematics. find that at fixed mass systematically decrease disordered motions increase rotation velocity potential well depth time....
The disc structure of the Milky Way is marked by a chemical dichotomy, with high-alpha and low-alpha abundance sequences, traditionally identified geometric thick thin discs. This identification aided old ages stars, lower average ones. Recent large scale surveys such as APOGEE have provided wealth data on this structure, including showing that an discs not exact, but origin dichotomy has remained unclear. Here we demonstrate arises naturally if early gas-rich fragments, leading to some...
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...
Abstract The recent UNCOVER survey with the James Webb Space Telescope (JWST) exploits nearby cluster A2744 to create deepest view of our Universe date by leveraging strong gravitational lensing. In this work, we perform photometric fitting more than 50,000 robustly detected sources out z ∼ 15. We show redshift evolution stellar ages, star formation rates, and rest-frame colors across full range 0.2 ≲ galaxy properties are inferred using Prospector Bayesian inference framework informative -...
We present the first comprehensive release of photometric redshifts (photo-z's) from Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) team. use statistics based upon Quantile-Quantile (Q--Q) plot to identify biases and signatures underestimated or overestimated errors in photo-z probability density functions (PDFs) produced by six groups collaboration; correcting for these effects makes resulting PDFs better match statistical definition a PDF. After each group's PDF,...
We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift 2 ⩽ z 2.5 with star formation rates SFR ∼ 100 M☉ yr−1 and masses log(M/M☉) ∼10.8. Their high integrated gas velocity dispersions σint km s−1, as measured from emission lines Hα [O iii], the resultant M⋆–σint relation M⋆–Mdyn all match well to those quiescent 2, stellar absorption lines. Since log(M⋆/Mdyn) =−0.06 ± 0.2 dex, these SFGs appear be dynamically relaxed evolved,...
Interpreting observations of distant galaxies in terms constraints on physical parameters - such as stellar mass, star-formation rate (SFR) and dust optical depth requires spectral synthesis modelling. We analyse the reliability these determined under commonly adopted `classical' assumptions: histories assumed to be exponentially declining functions time, a simple law no emission-line contribution. Improved modelling techniques data quality now allow us use more sophisticated approach,...