相关论文: New Constraints on Cosmic Reionization from the 20…

We present the 2012 Hubble Ultra Deep Field campaign (UDF12), a large 128-orbit Cycle 19 \HST\ program aimed at extending previous WFC3/IR observations of the UDF by quadrupling the exposure time in the F105W filter, imaging in an…

We present the results of the deepest search to date for star-forming galaxies beyond a redshift z~8.5 utilizing a new sequence of near-infrared Wide Field Camera 3 images of the Hubble Ultra Deep Field. This `UDF12' campaign completed in…

We determine the abundance of i'-band drop-outs in the recently-released HST/ACS Hubble Ultra Deep Field (UDF). Since the majority of these sources are likely to be z~6 galaxies whose flux decrement between the F775W i'-band and F850LP…

We use deep Hubble Space Telescope imaging of the Frontier Fields to accurately measure the galaxy rest-frame ultraviolet luminosity function (UV LF) in the redshift range $z \sim 6-8$. We combine observations in three lensing clusters…

We present a catalog of high redshift star-forming galaxies selected to lie within the redshift range z ~ 7-8 using the Ultra Deep Field 2012 (UDF12), the deepest near-infrared (near-IR) exposures yet taken with the Hubble Space Telescope.…

We have searched for star-forming galaxies at z~7 by applying the Lyman-break technique to newly-released 1.1micron Y-band images from WFC3 on HST. By comparing these images of the Hubble Ultra Deep Field with the ACS z'-band (0.85micron),…

We compare the available catalogs of $z\approx6$ galaxies in the Hubble Ultra-Deep Field (UDF) and in the Great Observatories Origins Deep Survey (GOODS) with the expected properties of the sources of cosmological reionization from our…

We present measurements of the specific ultraviolet luminosity density from a sample of 483 galaxies at 6<z<8. These galaxies were selected from new deep near-infrared HST imaging from the CANDELS, HUDF09 and ERS programs. In contrast to…

We discuss new constraints on the epoch of cosmic reionization and test the assumption that most of the ionizing photons responsible arose from high redshift star-forming galaxies. Good progress has been made in charting the end of…

We present photometry and derived redshifts from up to eleven bandpasses for 9927 galaxies in the Hubble Ultra Deep field (UDF), covering an observed wavelength range from the near-ultraviolet (NUV) to the near-infrared (NIR) with Hubble…

Studies of the Hubble Deep Field (HDF) and other deep surveys have revealed an apparent peak in the ultraviolet (UV) luminosity density, and therefore the star-formation rate density, of the Universe at redshifts 1<z<2. We use photometric…

The installation of the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) will revolutionize the study of high-redshift galaxy populations. Initial observations of the HST Ultra Deep Field (UDF) have yielded multiple z>~7…

We analyze the redshift- and luminosity-dependent sizes of dropout galaxy candidates in the redshift range z~7-12 using deep images from the UDF12 campaign, data which offers two distinct advantages over that used in earlier work. Firstly,…

Studies of the Hubble Deep Field (HDF) and other deep surveys have revealed an apparent peak in the ultraviolet (UV) luminosity density, and therefore the star-formation rate density, of the Universe at redshifts 1<z<2. We use photometric…

Studying the formation and evolution of galaxies at the earliest cosmic times, and their role in reionization, requires the deepest imaging possible. Ultra-deep surveys like the HUDF and HFF have pushed to mag \mAB$\,\sim\,$30, revealing…

Looking for bright galaxies born in the early universe is fundamental to investigating the Epoch of Reionization, the era when the first stars and galaxies ionized the intergalactic medium. We utilize Hubble Space Telescope pure parallel…

We use the new ultra-deep, near-infrared imaging of the Hubble Ultra-Deep Field (HUDF) provided by our UDF12 HST WFC3/IR campaign to explore the rest-frame UV properties of galaxies at redshifts z > 6.5. We present the first unbiased…

Recent suggestions of a "photon underproduction crisis" (Kollmeier \etal\ 2014) have generated concern over the intensity and spectrum of ionizing photons in the metagalactic ultraviolet background (UVB). The balance of hydrogen…

[Abridged] We detect three (plus one less certain) z-dropout sources in two separate fields of our UDF05 HST NICMOS images. These z~7 Lyman-Break Galaxy (LBG) candidates allow us to constrain the Luminosity Function (LF) of the star forming…

Current data of high-redshift absorption-line systems imply that hydrogen reionization occurred before redshifts of about 5. Previous works on reionization by the first stars or quasars have shown that such scenarios are described by a…