Search Publications
The Thermal Reprocessing of Reflected Radiation in the AGN Accretion Disk
Wang, Jiancheng; Zhong, Xiaogu
We present a reflected reprocessing model to study the thermal lag-wavelength relationship in the AGN accretion disk. The main radiation produced from the corona assumed with the lamppost geometry on the axis of the black hole irradiates the accretion disk to affect the temperature structure via reflection processes. Considering the thermal emissi…
Dark X-Ray Galaxies in the A1367 Galaxy Cluster
Henriksen, Mark J.; Dusek, Scott
We have characterized a sample of extended X-ray sources in the A1367 galaxy cluster that lack optical counterparts. The sources are galaxy size and have an average total mass of 1.3 × 1011 solar masses. The average hot gas mass is 3.0 × 109 solar masses and the average X-ray luminosity is 4.3 × 1041 erg cm-2<…
Anomalous Hα Emission Line Profile Detected at the Center of DDO 53
McQuinn, Kristen B. W.; van Zee, Liese; Hunter, Laura C. +1 more
We present the detection of a very broad (FWHM = 670 ± 17 km s-1), low-intensity Hα emission line component near the center of DDO 53, a star-forming dwarf irregular galaxy located in the M81 group. The broad component is found at the base of a bright and narrow (FWHM = 38 ± 2 km s-1) component. Using WIYN/Sparsepak optical s…
The Milky Way Project: Probing Star Formation with First Results on Yellowballs from DR2
Wolf-Chase, Grace; Kerton, C. R.; Devine, Kathryn +7 more
Yellowballs (YBs) were first discovered during the Milky Way Project (MWP) citizen science initiative. The MWP users noticed compact, yellow regions in Spitzer Space Telescope mid-infrared (MIR) images of the Milky Way plane and asked professional astronomers to explain these "yellow balls." Follow-up work by Kerton et al. determined that YBs like…
Asymmetric Distribution of the Solar Photospheric Magnetic-Field Values
Gao, Peng-Xin; Li, Ke-Jun; Xu, Jing-Chen
Understanding the characteristics of the solar magnetic field is essential for interpreting solar activities and dynamo. In this research, we investigated the asymmetric distribution of the solar photospheric magnetic-field values, using synoptic charts constructed from space-borne high-resolution magnetograms. It is demonstrated that the Lorentzi…
The Nonrelaxation of Magnetic Field Lines in Solar Wind Magnetic Reconnection Exhausts
Xu, Qi; Xu, Xiaojun; Xu, Jiaying +2 more
We present a case study using data from multiple spacecraft and statistics from the ACE spacecraft to investigate the relaxation of reconnected magnetic field lines in solar wind magnetic reconnection exhausts, which constitute one of the two outflow regions resulting from magnetic reconnection, and which are often characterized by a plasma jet, m…
The Galaxy Environment of Extremely Massive Quasars. I. An Overdensity of Hα Emitters at z = 1.47
Im, Myungshin; Jun, Hyunsung D.; Hyun, Minhee +8 more
We measure a strong excess in the galaxy number density around PG 1630+377, an extremely massive (MBH ≃ 109.7M⊙) quasar at z = 1.475, using near-infrared narrowband imaging. We identify 79 narrow H-band excess objects in a 525 arcmin2 area including the vicinity and surroundings of the quasar. These sour…
Calibration of the Tip of the Red Giant Branch
Madore, Barry F.; Freedman, Wendy L.; Lee, Myung Gyoon +6 more
The tip of the red giant branch (TRGB) method provides one of the most accurate and precise means of measuring the distances to nearby galaxies. Here we present a multi-wavelength, VIJHK absolute calibration of the TRGB based on observations of TRGB stars in the Large Magellanic Cloud (LMC), grounded on a geometric distance, determined by detached…
Evidence from the H3 Survey That the Stellar Halo Is Entirely Comprised of Substructure
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +5 more
In the ΛCDM paradigm, the Galactic stellar halo is predicted to harbor the accreted debris of smaller systems. To identify these systems, the H3 Spectroscopic Survey, combined with Gaia, is gathering 6D phase-space and chemical information in the distant Galaxy. Here we present a comprehensive inventory of structure within 50 kpc from the Galactic…
The SunPy Project: Open Source Development and Status of the Version 1.0 Core Package
Ryan, Daniel F.; Murray, Sophie A.; Ireland, Jack +32 more
The goal of the SunPy project is to facilitate and promote the use and development of community-led, free, and open source data analysis software for solar physics based on the scientific Python environment. The project achieves this goal by developing and maintaining the sunpy core package and supporting an ecosystem of affiliated packages. This …