Search Publications
Excess in the High-frequency Radio Background: Insights from Planck
Chary, Ranga-Ram; Murphy, Eric J.
We conduct a stacking analysis using the combination of 1.4 GHz detections in the NRAO VLA Sky Survey (NVSS) and Planck all-sky maps to estimate the differential source counts down to the few 100 µJy level at 30, 44, 70, and 100 GHz. Using these source count estimates, we are able to measure the integrated extragalactic background light from…
Spectroscopic Measurements of the Ion Velocity Distribution at the Base of the Fast Solar Wind
Fletcher, Lyndsay; Jeffrey, Natasha L. S.; Savin, Daniel W. +1 more
In situ measurements of the fast solar wind reveal non-thermal distributions of electrons, protons, and minor ions extending from 0.3 au to the heliopause. The physical mechanisms responsible for these non-thermal properties and the location where these properties originate remain open questions. Here, we present spectroscopic evidence, from extre…
Magnetic Structure of a Composite Solar Microwave Burst
Masuda, Satoshi; Liu, Chang; White, Stephen M. +2 more
A composite flare consisting of an impulsive flare SOL2015-06-21T01:42 (GOES class M2.0) and a more gradual, long-duration flare SOL2015-06-21T02:36 (M2.6) from NOAA Active Region 12371, is studied using observations with the Nobeyama Radioheliograph (NoRH) and the Solar Dynamics Observatory (SDO). While composite flares are defined by their chara…
X-Ray Observations of Magnetar SGR 0501+4516 from Outburst to Quiescence
Ng, C. -Y.; Mong, Y. -L.
Magnetars are neutron stars having extreme magnetic field strengths. Study of their emission properties in quiescent state can help understand effects of a strong magnetic field on neutron stars. SGR 0501+4516 is a magnetar that was discovered in 2008 during an outburst, which has recently returned to quiescence. We report its spectral and timing …
Theoretically Motivated Search and Detection of Non-thermal Pulsations from PSRs J1747-2958, J2021+3651, and J1826-1256
Rea, Nanda; Coti Zelati, Francesco; Torres, Diego F. +3 more
Based on a theoretical selection of pulsars as candidates for detection at X-ray energies, we present an analysis of archival X-ray observations performed with Chandra and XMM-Newton of PSR J1747-2958 (the pulsar in the “Mouse” nebula), PSR J2021+3651 (the pulsar in the “Dragonfly” nebula), and PSR J1826-1256. X-ray pulsations from PSR J1747-2958 …
On the Radial Metallicity Gradient and Radial Migration Effect of the Galactic Disk
Zhao, Gang; Chen, Yuqin; Li, Chengdong +4 more
We study the radial metallicity gradient Δ[M/H]/ΔR g as a function of [Mg/Fe] and | Z| with the help of a guiding radius based on the Apache Point Observatory Galactic Evolution Experiment and Gaia and then analyze the radial migration effect on the radial metallicity gradient and metallicity-rotation gradient between the Galactic thi…
Magnetic Field Uniformity Across the GF 9-2 YSO, L1082C Dense Core, and GF 9 Filamentary Dark Cloud
Pillai, T.; Cerny, C.; Clemens, Dan P. +3 more
The orientation of the magnetic field (B field) in the filamentary dark cloud GF 9 was traced from the periphery of the cloud into the L1082C dense core that contains the low-mass, low-luminosity Class 0 young stellar object (YSO) GF 9-2 (IRAS 20503+6006). This was done using SOFIA HAWC+ dust thermal emission polarimetry (TEP) at 216 µm in c…
The JCMT Gould Belt Survey: A First Look at the Auriga-California Molecular Cloud with SCUBA-2
White, G. J.; Wilson, C. D.; Di Francesco, J. +57 more
We present 850 and 450 µm observations of the dense regions within the Auriga-California molecular cloud using SCUBA-2 as part of the JCMT Gould Belt Legacy Survey to identify candidate protostellar objects, measure the masses of their circumstellar material (disk and envelope), and compare the star formation to that in the Orion A molecular…
Disturbed Fossil Group Galaxy NGC 1132
Trinchieri, Ginevra; Fabbiano, Giuseppina; O'Sullivan, Ewan +10 more
We have analyzed the Chandra archival data of NGC 1132, a well-known fossil group, i.e., a system expected to be old and relaxed long after the giant elliptical galaxy assembly. Instead, the Chandra data reveal that the hot gas morphology is disturbed and asymmetrical, with a cold front following a possible bow shock. We discuss possible origins o…
Relativistic Astronomy
Zhang, Bing; Li, Kunyang
The “Breakthrough Starshot” aims at sending near-speed-of-light cameras to nearby stellar systems in the future. Due to the relativistic effects, a transrelativistic camera naturally serves as a spectrograph, a lens, and a wide-field camera. We demonstrate this through a simulation of the optical-band image of the nearby galaxy M51 in the rest fra…