Search Publications
Spitzer Observations of Extended Lyman-α Clouds in the SSA22 Field
Egami, E.; Yamada, T.; Matsuda, Y. +5 more
We present the results of a Spitzer IRAC and MIPS 24 µm study of extended Lyman-α clouds (or Lyman-α Blobs, LABs) within the SSA22 filamentary structure at z = 3.09. We detect 6/26 LABs in all IRAC filters, four of which are also detected at 24 µm, and find good correspondence with the 850 µm measurements of Geach et al. An analy…
Bright Strongly Lensed Galaxies at Redshift z ~ 6-7 behind the Clusters Abell 1703 and CL0024+16
Ford, H. C.; Infante, L.; Zheng, W. +10 more
We report on the discovery of three bright, strongly lensed objects behind Abell 1703 and CL0024+16 from a dropout search over 25 arcmin2 of deep NICMOS data, with deep ACS optical coverage. They are undetected in the deep ACS images below 8500 Å and have clear detections in the J and H bands. Fits to the ACS, NICMOS, and IRAC data yiel…
X-ray Insights into the Physics of Mini-BAL Quasar Outflows
Brandt, W. N.; Schneider, Donald P.; Gallagher, S. C. +1 more
We examine the ultraviolet and X-ray properties of 256 radio-quiet Sloan Digital Sky Survey quasars (QSOs) observed in X-rays with Chandra and/or XMM-Newton in order to study the relationship between QSOs with broad C IV absorption lines (BALs; width >2000 km s-1) and those with C IV mini-BALs (here defined to have widths of 1000-200…
The Nature of Optically Dull Active Galactic Nuclei in COSMOS
Kartaltepe, Jeyhan S.; Koekemoer, Anton M.; Trump, Jonathan R. +17 more
We present infrared, optical, and X-ray data of 48 X-ray bright, optically dull active galactic nuclei (AGNs) in the COSMOS field. These objects exhibit the X-ray luminosity of an AGN but lack broad and narrow emission lines in their optical spectrum. We show that despite the lack of optical emission lines, most of these optically dull AGNs are no…
The 5.25 and 5.7 µm Astronomical Polycyclic Aromatic Hydrocarbon Emission Features
Tielens, A. G. G. M.; Boersma, C.; Allamandola, L. J. +3 more
Astronomical mid-IR spectra show two minor polycyclic aromatic hydrocarbon (PAH) features at 5.25 and 5.7 µm (1905 and 1754 cm-1) that hitherto have been little studied, but contain information about the astronomical PAH population that complements that of the major emission bands. Here, we report a study involving both laboratory…
Implosion in a Coronal Eruption
Wang, Haimin; Liu, Rui; Alexander, David
We present the observations of the contraction of the extreme-ultraviolet coronal loops overlying the flaring region during the preheating as well as the early impulsive phase of a GOES class C8.9 flare. During the relatively long, 6 minutes, preheating phase, hard X-ray (HXR) count rates at lower energies (below 25 keV) as well as soft X-ray flux…
Asymmetric Eruptive Filaments
Liu, Rui; Alexander, David; Gilbert, Holly R.
Filaments are often observed to erupt asymmetrically, during which one leg is fixed to the photosphere (referred to as the anchored leg) while the other undertakes most of the dynamic motions (referred to as the active leg) during the eruptive process. In this paper, we present observations of a group of asymmetric eruptive filaments, in which two…
First Direct Metallicity Measurement Of a Lensed Star-Forming Galaxy at z = 1.7
Yuan, T. -T.; Kewley, L. J.
We present the rest-frame optical spectrum of a strongly lensed galaxy at redshift z = 1.7 behind the cluster Abell 1689. We detect the temperature sensitive auroral line [O III] λ4363, which allows the first direct metallicity measurement for galaxies at z > 1. Our high signal-to-noise spectrum indicates that the target is an extremely low met…
Supersonic Downflows in a Sunspot Light Bridge
Venkatakrishnan, P.; Mathew, Shibu K.; Louis, Rohan E. +1 more
We report the discovery of supersonic downflows in a sunspot light bridge using measurements taken with the spectropolarimeter onboard the Hinode satellite. The downflows occur in small patches close to regions where the vector magnetic field changes orientation rapidly, and are associated with anomalous circular polarization profiles. An inversio…
Rotation of White-light Coronal Mass Ejection Structures as Inferred from LASCO Coronagraph
Yurchyshyn, Vasyl; Abramenko, Valentyna; Tripathi, Durgesh
Understanding the connection between the magnetic configurations of a coronal mass ejection (CME) and their counterpart in the interplanetary medium is very important in terms of space weather predictions. Our previous findings indicate that the orientation of a halo CME elongation may correspond to the orientation of the underlying flux rope. Her…