Search Publications
The Properties of the Galactic Hot Gaseous Halo from X-Ray Emission
Li, Yunyang; Bregman, Joel
The extended hot X-ray emitting gaseous halo of the Milky Way has an optical depth ∼1 for the dominant emission lines of O vii and O viii, which are used to infer the halo properties. To improve on halo gas properties, we treat optical depth effects with a Monte Carlo radiative transfer model, which leads to slightly steeper density profiles (β ≈ …
Surge-like Oscillations above Sunspot Light Bridges Driven by Magnetoacoustic Shocks
He, Jiansen; Tian, Hui; Zhang, Jingwen +1 more
High-resolution observations of the solar chromosphere and transition region often reveal surge-like oscillatory activities above sunspot light bridges (LBs). These oscillations are often interpreted as intermittent plasma jets produced by quasi-periodic magnetic reconnection. We have analyzed the oscillations above an LB in a sunspot using data t…
The Bright and Dark Sides of High-redshift Starburst Galaxies from Herschel and Subaru Observations
Daddi, E.; Rodighiero, G.; Sanders, D. B. +15 more
We present rest-frame optical spectra from the FMOS-COSMOS survey of 12 z ∼ 1.6 Herschel starburst galaxies, with star formation rate (SFR) elevated by ×8, on average, above the star-forming main sequence (MS). Comparing the Hα to IR luminosity ratio and the Balmer decrement, we find that the optically thin regions of the sources contain on averag…
Observations of the Formation, Development, and Structure of a Current Sheet in an Eruptive Solar Flare
Seaton, Daniel B.; Bartz, Allison E.; Darnel, Jonathan M.
We present Atmospheric Imaging Assembly observations of a structure we interpret as a current sheet associated with an X4.9 flare and coronal mass ejection that occurred on 2014 February 25 in NOAA Active Region 11990. We characterize the properties of the current sheet, finding that the sheet remains on the order of a few thousand kilometers thic…
CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging
Elvis, Martin; Raymond, John; Storchi-Bergmann, Thaisa +5 more
The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images …
Identification of Low Coronal Sources of “Stealth” Coronal Mass Ejections Using New Image Processing Techniques
Morgan, Huw; Alzate, Nathalia
Coronal mass ejections (CMEs) are generally associated with low coronal signatures (LCSs), such as flares, filament eruptions, extreme ultraviolet (EUV) waves, or jets. A number of recent studies have reported the existence of stealth CMEs as events without LCSs, possibly due to observational limitations. Our study focuses on a set of 40 stealth C…
IRIS, Hinode, SDO, and RHESSI Observations of a White Light Flare Produced Directly by Nonthermal Electrons
Lee, Kyoung-Sun; Brooks, David H.; Watanabe, Kyoko +2 more
An X1.6 flare occurred in active region AR 12192 on 2014 October 22 at 14:02 UT and was observed by Hinode, IRIS, SDO, and RHESSI. We analyze a bright kernel that produces a white light (WL) flare with continuum enhancement and a hard X-ray (HXR) peak. Taking advantage of the spectroscopic observations of IRIS and Hinode/EIS, we measure the tempor…
The Eruption of a Small-scale Emerging Flux Rope as the Driver of an M-class Flare and of a Coronal Mass Ejection
Yan, X. L.; Jiang, C. W.; Xue, Z. K. +6 more
Solar flares and coronal mass ejections are the most powerful explosions in the Sun. They are major sources of potentially destructive space weather conditions. However, the possible causes of their initiation remain controversial. Using high-resolution data observed by the New Solar Telescope of Big Bear Solar Observaotry, supplemented by Solar D…
Detection of a Large Population of Ultradiffuse Galaxies in Massive Galaxy Clusters: Abell S1063 and Abell 2744
Lee, Myung Gyoon; Lee, Jeong Hwan; Kang, Jisu +1 more
We present the detection of a large population of ultradiffuse galaxies (UDGs) in two massive galaxy clusters, Abell S1063 at z = 0.348 and Abell 2744 at z = 0.308, based on F814W and F105W images in the Hubble Frontier Fields Program. We find 47 and 40 UDGs in Abell S1063 and Abell 2744, respectively. Color-magnitude diagrams of the UDGs show tha…
Old but Still Warm: Far-UV Detection of PSR B0950+08
Pavlov, G. G.; Guillot, S.; Kargaltsev, O. +3 more
We report on a Hubble Space Telescope detection of the nearby, old pulsar B0950+08 (d≃ 262 pc, spin-down age 17.5 Myr) in two far-ultraviolet (FUV) bands. We measured the mean flux densities {\bar{f}}ν =109+/- 6 nJy and 83 ± 14 nJy in the F125LP and F140LP filters (pivot wavelengths 1438 and 1528 Å). Using the FUV data together with pre…