Search Publications
How to Channel Photospheric Oscillations into the Corona
Erdélyi, R.; De Pontieu, B.; De Moortel, I.
There are now many observations of waves in the solar corona with periods around 5 minutes. The source of these waves is uncertain, although global p-modes in the photosphere are an obvious candidate, given the similarity of the dominant periods. However, p-modes are traditionally considered evanescent in the upper photosphere, and it has been unc…
Cepheid Calibrations from the Hubble Space Telescope of the Luminosity of Two Recent Type Ia Supernovae and a Redetermination of the Hubble Constant
Filippenko, Alexei V.; Riess, Adam G.; Challis, Peter M. +6 more
We report observations of two nearby Type Ia supernovae (SNe Ia) for which observations of Cepheid variables in the host galaxies have been obtained with the Hubble Space Telescope: SN 1994ae in NGC 3370 and SN 1998aq in NGC 3982. For NCG 3370, we used the Advanced Camera for Surveys to observe 64 Cepheids that yield a distance of 29 Mpc, the fart…
Multiphase High-Velocity Clouds toward HE 0226-4110 and PG 0953+414
Tripp, Todd M.; Sembach, Kenneth R.; Savage, Blair D. +3 more
We study the physical conditions, elemental abundances, and kinematics of the high-velocity clouds (HVCs) along the sight lines toward active galaxies HE 0226-4110 and PG 0953+414 using Hubble Space Telescope Space Telescope Imaging Spectrograph and Far Ultraviolet Spectroscopic Explorer data. No 21 cm H I emission is detected in these clouds, but…
Imaging Redshifts of BL Lacertae Objects
Sbarufatti, B.; Falomo, R.; Treves, A.
The HST snapshot imaging survey of 110 BL Lac objects (Urry et al.) has clearly shown that the host galaxies are massive and luminous ellipticals. The dispersion of the absolute magnitudes is sufficiently small that the measurement of the galaxy brightness becomes a valuable way of estimating their distance. This is illustrated by constructing a H…
The DEEP Groth Strip Galaxy Redshift Survey. III. Redshift Catalog and Properties of Galaxies
Weiner, Benjamin J.; Forbes, Duncan A.; Rhodes, Jason +16 more
The Deep Extragalactic Evolutionary Probe (DEEP) is a series of spectroscopic surveys of faint galaxies, targeted at understanding the properties and clustering of galaxies at redshifts z~1. We present the redshift catalog of the DEEP1 Groth Strip pilot phase of this project, a Keck LRIS survey of faint galaxies in the Groth Survey Strip imaged wi…
The Murmur of the Sleeping Black Hole: Detection of Nuclear Ultraviolet Variability in LINER Galaxies
Maoz, Dan; Nagar, Neil M.; Wilson, Andrew S. +1 more
LINER nuclei, which are present in many nearby galactic bulges, may be the manifestation of low-rate or low-radiative-efficiency accretion onto supermassive central black holes. However, it has been unclear whether the compact UV nuclear sources present in many LINERs are clusters of massive stars, rather than being directly related to the accreti…
On the Polar Caps of the Three Musketeers
Caraveo, P. A.; Bignami, G. F.; Mereghetti, S. +2 more
XMM-Newton EPIC observations of PSR B0656+14, PSR B1055-52, and Geminga have substantially increased the collection of statistics available for these three isolated neutron stars, so apparently similar to deserve the nickname of the Three Musketeers, given to them by Becker & Trümper. Here we take advantage of the EPIC statistics to perform ph…
Evidence for a Massive Poststarburst Galaxy at z~6.5
Panagia, N.; Stern, D.; Dickinson, M. +28 more
We describe results from a search for high-redshift J-band ``dropout'' galaxies in the portion of the Great Observatories Origins Deep Survey (GOODS) southern field that is covered by extremely deep imaging from the Hubble Ultradeep Field (HUDF). Using observations at optical, near-infrared, and mid-infrared wavelengths from the Hubble and Spitzer…
High-Energy Gamma Rays from the Massive Black Hole in the Galactic Center
Aharonian, F.; Neronov, A.
Accreting black holes (BHs) are believed to be sites of possible particle acceleration with conditions that are also favorable for effective gamma-ray production. However, because of photon-photon pair production, only low-energy (MeV) gamma rays can escape these compact objects with typically very large compactness parameters, κ=(L/LEdd
Quasars and the Big Blue Bump
Kaiser, Mary Elizabeth; Green, Richard F.; Kriss, Gerard A. +10 more
We investigate the ultraviolet-to-optical spectral energy distributions of 17 active galactic nuclei (AGNs) using quasi-simultaneous spectrophotometry spanning 900-9000 Å (rest frame). We employ data from the Far Ultraviolet Spectroscopic Explorer, the Hubble Space Telescope, and the 2.1 m telescope at Kitt Peak National Observatory. Taking advant…