Search Publications
Magnetic Fields of an Active Region Filament from Full Stokes Analysis of Si I 1082.7 nm and He I 1083.0 nm
Liu, Y.; Lagg, A.; Solanki, S. +1 more
Vector magnetic fields of an active region filament in the photosphere and upper chromosphere are obtained from spectro-polarimetric observations recorded with the Tenerife Infrared Polarimeter (TIP II) at the German Vacuum Tower Telescope. We apply Milne-Eddington inversions on full Stokes vectors of the photospheric Si I 1082.7 nm and the upper …
Measuring Microlensing Using Spectra of Multiply Lensed Quasars
Muñoz, J. A.; Mediavilla, E.; Motta, V. +1 more
We report on a program of spectroscopic observations of gravitationally lensed QSOs with multiple images. We seek to establish whether microlensing is occurring in each QSO image using only single-epoch observations. We calculate flux ratios for the cores of emission lines in image pairs to set a baseline for no microlensing. The offset of the con…
Velocity and Magnetic Transients Driven by the X2.2 White-light Flare of 2011 February 15 in NOAA 11158
Maurya, R. A.; Ambastha, A.; Vemareddy, P.
The first X-class flare of the current solar cycle 24 occurred in Active Region NOAA 11158 during its central meridian passage on 2011 February 15. This two-ribbon white-light flare was observed by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory. During the peak phase of the flare, we detected magnetic and Dopple…
A 30 AU Radius CO Gas Hole in the Disk around the Herbig Ae Star Oph IRS 48
van Dishoeck, E. F.; Pontoppidan, K. M.; Herczeg, G. J. +1 more
The physical processes leading to the disappearance of disks around young stars are not well understood. A subclass of transitional disks, the so-called cold disks with large inner dust holes, provides a crucial laboratory for studying disk dissipation processes. IRS 48 has a 30 AU radius hole previously measured from dust continuum imaging at 18.…
The Coronal Source of Extreme-ultraviolet Line Profile Asymmetries in Solar Active Region Outflows
Warren, Harry P.; Brooks, David H.
High-resolution spectra from the Hinode EUV Imaging Spectrometer have revealed that coronal spectral line profiles are sometimes asymmetric, with a faint enhancement in the blue wing on the order of 100 km s-1. These asymmetries could be important since they may be subtle yet diagnostically useful signatures of coronal heating or solar …
The Hubble Space Telescope Cluster Supernova Survey. II. The Type Ia Supernova Rate in High-redshift Galaxy Clusters
Gladders, M. D.; Panagia, N.; Huang, X. +41 more
We report a measurement of the Type Ia supernova (SN Ia) rate in galaxy clusters at 0.9 < z < 1.46 from the Hubble Space Telescope Cluster Supernova Survey. This is the first cluster SN Ia rate measurement with detected z > 0.9 SNe. Finding 8 ± 1 cluster SNe Ia, we determine an SN Ia rate of 0.50+0.23 -0.19 (stat)
Resolving the Galaxies within a Giant Lyα Nebula: Witnessing the Formation of a Galaxy Group?
Dey, Arjun; Jannuzi, Buell T.; Soifer, B. T. +8 more
Detailed analysis of the substructure of Lyα nebulae can put important constraints on the physical mechanisms at work and the properties of galaxies forming within them. Using high-resolution Hubble Space Telescope (HST) imaging of a Lyα nebula at z ≈ 2.656, we have taken a census of the compact galaxies in the vicinity, used optical/near-infrared…
Morphological Evolution of a Three-dimensional Coronal Mass Ejection Cloud Reconstructed from Three Viewpoints
Feng, L.; Inhester, B.; Wei, Y. +3 more
The propagation properties of coronal mass ejections (CMEs) are crucial to predict its geomagnetic effect. A newly developed three-dimensional (3D) mask fitting reconstruction method using coronagraph images from three viewpoints has been described and applied to the CME ejected on 2010 August 7. The CME's 3D localization, real shape, and morpholo…
On the Role of the Accretion Disk in Black Hole Disk-Jet Connections
Fabian, A. C.; Miller, J. M.; Nowak, M. A. +5 more
Models of jet production in black hole systems suggest that the properties of the accretion disk—such as its mass accretion rate, inner radius, and emergent magnetic field—should drive and modulate the production of relativistic jets. Stellar-mass black holes in the "low/hard" state are an excellent laboratory in which to study disk-jet connection…
Early-type Galaxies at z ~ 1.3. IV. Scaling Relations in Different Environments
Demarco, R.; Tanaka, M.; Rosati, P. +15 more
We present the Kormendy and mass-size relations (MSR) for early-type galaxies (ETGs) as a function of environment at z ~ 1.3. Our sample includes 76 visually classified ETGs with masses 1010 < M/M ⊙ < 1011.5, selected in the Lynx supercluster and in the Great Observatories Origins Deep Survey/Chandra Deep Fie…