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Young, Blue, and Isolated Stellar Systems in the Virgo Cluster. II. A New Class of Stellar System
Cresci, Giovanni; Cannon, John M.; Haynes, Martha P. +21 more
We discuss five blue stellar systems in the direction of the Virgo cluster, analogous to the enigmatic object SECCO 1 (AGC 226067). These objects were identified based on their optical and UV morphology and followed up with H I observations with the Very Large Array (and Green Bank Telescope), Multi Unit Spectroscopic Explorer (on the Very Large T…
New Results from the Spectral Observations of Solar Coronal Type II Radio Bursts
Ramesh, R.; Kathiravan, C.; Natarajan, S. Surya
We carried out a statistical study of twenty-six type II radio bursts from the Sun observed with the Gauribidanur Low-frequency Solar Spectrograph in the frequency range 85-35 MHz during the period 2009-2019. Our results indicate that the average instantaneous bandwidth of the type II bursts in the above frequency range correlates with the angular…
Broadband X-Ray Spectral Analysis of the Dual AGN System Mrk 739
Tanimoto, Atsushi; Ueda, Yoshihiro; Ricci, Claudio +4 more
We present the result of a broadband (0.5-70 keV) X-ray spectral analysis of the late-merger galaxy Mrk 739, which contains a dual active galactic nucleus (AGN), Mrk 739E and Mrk 739W, with a separation of ≈3.4 kpc. The spectra obtained with NuSTAR, Chandra, XMM-Newton, and Swift/BAT are simultaneously analyzed by separating the contributions from…
Spectra of Cosmic-Ray Sodium and Aluminum and Unexpected Aluminum Excess
Jóhannesson, G.; Moskalenko, I. V.; Porter, T. A. +11 more
Since its launch, the Alpha Magnetic Spectrometer-02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species, $\bar{p}$ , e ±, and nuclei (H-Si, Fe), which resulted in a number of breakthroughs. The most recent AMS-02 result is the measurement of the spectra of CR sodium and aluminum up to ~2 TV…
Discovery of Year-scale Time Variability from Thermal X-Ray Emission in Tycho's Supernova Remnant
Yamaguchi, Hiroya; Uchida, Hiroyuki; Tsuru, Takeshi Go +2 more
Mechanisms of particle heating are crucial to understanding the shock physics in supernova remnants (SNRs). However, there has been little information on time variabilities of thermalized particles so far. Here, we present a discovery of a gradually brightening thermal X-ray emission found in the Chandra data of Tycho's SNR obtained during 2000-20…
Polarization from Aligned Dust Grains in the β Pic Debris Disk
Hughes, A. Meredith; Hull, Charles L. H.; Le Gouellec, Valentin J. M. +8 more
We present 870 µm Atacama Large Millimeter/submillimeter Array polarization observations of thermal dust emission from the iconic, edge-on debris disk β Pic. While the spatially resolved map does not exhibit detectable polarized dust emission, we detect polarization at the ~3σ level when averaging the emission across the entire disk. The cor…
An Optical Spectrum of the Diffuse Galactic Light from BOSS and IRIS
Hensley, Brandon S.; Brandt, Timothy D.; Draine, Bruce T. +2 more
We present a spectrum of the diffuse Galactic light (DGL) between 3700 and 10,000 Å, obtained by correlating optical sky intensity with far-infrared dust emission. We use nearly 250,000 blank-sky spectra from BOSS/SDSS-III together with IRIS-reprocessed maps from the IRAS satellite. The larger sample size compared to SDSS-II results in a factor-of…
A White Dwarf-Main-sequence Binary Unveiled by Time-domain Observations from LAMOST and TESS
Liu, Jifeng; Zong, Weikai; Bai, Yu +16 more
We report a single-lined white dwarf-main-sequence binary system, LAMOST J172900.17+652952.8, which is discovered by the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST)'s medium-resolution time-domain surveys. The radial-velocity semi-amplitude and orbital period of the optical visible star are measured by using follow-up observ…
Validation and Interpretation of a Three-dimensional Configuration of a Magnetic Cloud Flux Rope
Qiu, Jiong; Hu, Qiang; Jian, Lan K. +3 more
One strong magnetic cloud (MC) with a magnetic field magnitude reaching ~40 nT at 1 au during 2012 June 16-17 is examined in association with a preexisting magnetic flux rope (MFR) identified on the Sun. The MC is characterized by a quasi-three-dimensional (3D) flux rope model based on in situ measurements from the Wind spacecraft. The contents of…
Further Evidence for the Minifilament-eruption Scenario for Solar Polar Coronal Jets
Savcheva, Antonia; Moore, Ronald L.; Savage, Sabrina L. +4 more
We examine a sampling of 23 polar-coronal-hole jets. We first identified the jets in soft X-ray (SXR) images from the X-ray telescope (XRT) on the Hinode spacecraft, over 2014-2016. During this period, frequently the polar holes were small or largely obscured by foreground coronal haze, often making jets difficult to see. We selected 23 jets among…