Steven Willner

Dr. Steven Willner

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Research Focus & Metrics

Academic Career Length

41Years (1986-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 May 2013 in The Astrophysical Journal
Verified
Journal Article
Closed access
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MAMatthew Ashby
Matthew Ashby
SWSteven Willner
Steven Willner
GFG. G. Fazio
G. G. Fazio
JHJ.-S. Huang
J.-S. Huang
RAR. Arendt
R. Arendt
HYH. Yan
H. Yan

14 December 2022 in The Astronomical Journal
Verified
Journal Article
Open access
RWRogier A. Windhorst
Rogier A. Windhorst
SCSeth H. Cohen
Seth H. Cohen
RJRolf A. Jansen
Rolf A. Jansen
JSJake Summers
Jake Summers
STScott Tompkins
Scott Tompkins
XZXiurui Zhao
Xiurui Zhao
We give an overview and describe the rationale, methods, and first results from NIRCam images of the JWST “Prime Extragalactic Areas for Reionization and Lensing Science” (PEARLS) project. PEARLS uses up to eight NIRCam filters to survey several prime extragalactic survey areas: two fields at the North Ecliptic Pole (NEP); seven gravitationally lensing clusters; two high redshift protoclusters; and the iconic backlit VV 191 galaxy system to map its dust attenuation. PEARLS also includes NIRISS spectra for one of the NEP fields and NIRSpec spectra of two high-redshift quasars. The main goal of PEARLS is to study the epoch of galaxy assembly, active galactic nucleus (AGN) growth, and First Light. Five fields—the JWST NEP Time-Domain Field (TDF), IRAC Dark Field, and three lensing clusters—will be observed in up to four epochs over a year. The cadence and sensitivity of the imaging data are ideally suited to find faint variable objects such as weak AGN, high-redshift supernovae, and cluster caustic transits. Both NEP fields have sightlines through our Galaxy, providing significant numbers of very faint brown dwarfs whose proper motions can be studied. Observations from the first spoke in the NEP TDF are public. This paper presents our first PEARLS observations, their NIRCam data reduction and analysis, our first object catalogs, the 0.9–4.5 μm galaxy counts and Integrated Galaxy Light. We assess the JWST sky brightness in 13 NIRCam filters, yielding our first constraints to diffuse light at 0.9–4.5 μm. PEARLS is designed to be of lasting benefit to the community.

1 April 2017 in The Astrophysical Journal Supplement Series
Verified
Journal Article
Open access
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MSMauro Stefanon
Mauro Stefanon
HYHaojing Yan
Haojing Yan
BMBahram Mobasher
Bahram Mobasher
GBGuillermo Barro
Guillermo Barro
JDJennifer L. Donley
Jennifer L. Donley
AWArjen van der Wel
Arjen van der Wel
We present a 0.4–8 μm multi-wavelength photometric catalog in the Extended Groth Strip (EGS) field. This catalog is built on the Hubble Space Telescope (HST) WFC3 and ACS data from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), and it incorporates the existing HST data from the All-wavelength Extended Groth strip International Survey (AEGIS) and the 3D-HST program. The catalog is based on detections in the F160W band reaching a depth of F160W = 26.62 AB (90% completeness, point sources). It includes the photometry for 41,457 objects over an area of arcmin2 in the following bands: HST/ACS F606W and F814W; HST WFC3 F125W, F140W, and F160W; Canada–France–Hawaii Telescope (CFHT)/Megacam u*, , , and CFHT/WIRCAM J, H, and K S; Mayall/NEWFIRM J1, J2, J3, H1, H2, and K; Spitzer IRAC 3.6, 4.5, 5.8, and 8.0 μm. We are also releasing value-added catalogs that provide robust photometric redshifts and stellar mass measurements. The catalogs are publicly available through the CANDELS repository.

25 July 2019 in The Astrophysical Journal Supplement Series
Verified
Journal Article
Closed access
GBGuillermo Barro
Guillermo Barro
PPPablo G. Pérez-González
Pablo G. Pérez-González
ACAntonio Cava
Antonio Cava
GBGabriel Brammer
Gabriel Brammer
VPViraj Pandya
Viraj Pandya
SWStijn Wuyts
Stijn Wuyts

1 September 2004 in The Astrophysical Journal Supplement Series
Verified
Journal Article
Closed access
PDF file
GFG. G. Fazio
G. G. Fazio
MAMatthew Ashby
Matthew Ashby
PBP. Barmby
P. Barmby
JHJoseph L. Hora
Joseph L. Hora
JHJ.‐S. Huang
J.‐S. Huang
EWE. L. Wright
E. L. Wright
Infrared source counts at wavelengths 3 < lambda < 10 um cover more than 10 magnitudes in source brightness, four orders of magnitude in surface density, and reach an integrated surface density of 10^5 sources/deg^2. At m<14 mag, most of the sources are Galactic stars, in agreement with models. After removal of Galactic stars, galaxy counts are consistent with what few measurements exist at nearby wavelengths. At 3.6 and 4.5 um, the galaxy counts follow the expectations of a Euclidean world model down to ~16 mag and drop below the Euclidean curve for fainter magnitudes. Counts at these wavelengths begin to show decreasing completeness around magnitude 19.5. At 5.8 and 8 um, the counts relative to a Euclidean world model show a large excess at bright magnitudes. This is probably because local galaxies emit strongly in the aromatic dust (``PAH'') features. The counts at 3.6 um resolve <50% of the Cosmic Infrared Background at that wavelength.Comment: ApJS (in press), in the Spitzer Space Telescope special issue; 14 pages, 2 color figures, 1 table (electronic only