Search Publications
Bubble in the Whale: Identifying the Optical Counterparts and Extended Nebula for the Ultraluminous X-Ray Sources in NGC 4631
Feng, Hua; Liu, Jifeng; Cai, Zheng +9 more
We present a deep optical imaging campaign on the starburst galaxy NGC 4631 with CFHT/MegaCam. By supplementing the HST/ACS and Chandra/ACIS archival data, we search for the optical counterpart candidates of the five brightest X-ray sources in this galaxy, four of which are identified as ultraluminous X-ray sources (ULXs). The stellar environments…
Estimating Coronal Mass Ejection Mass and Kinetic Energy by Fusion of Multiple Deep-learning Models
Wang, Haimin; Yurchyshyn, Vasyl; Li, Jialiang +5 more
Coronal mass ejections (CMEs) are massive solar eruptions, which have a significant impact on Earth. In this paper, we propose a new method, called DeepCME, to estimate two properties of CMEs, namely, CME mass and kinetic energy. Being able to estimate these properties helps better understand CME dynamics. Our study is based on the CME catalog mai…
Climatological Gravity Waves in the Middle and Upper Atmosphere of Mars Based on ACS/TGO Observations
Zhang, Yun; Zhang, Jie; Ji, Qianqian +2 more
Gravity waves (GWs) are important for the vertical coupling of the Martian atmosphere. The middle atmosphere is the key region where GWs propagate to the upper thermosphere and generate momentum and energy exchange, but the knowledge of middle-atmosphere GWs is incomplete, due to the lack of observations with the kilometer-scale resolution. We hav…
The Radiation Environments of Middle-aged F-type Stars
France, K.; Hinton, P. C.; Fleming, B. +5 more
Far-ultraviolet (FUV) emission lines from dwarf stars are important driving sources of photochemistry in planetary atmospheres. Properly interpreting spectral features of planetary atmospheres critically depends on the emission of its host star. While the spectral energy distributions (SEDs) of K- and M-type stars have been extensively characteriz…
Accretion Disk Wind of Hercules X-1 during the Short High State
Fabian, A. C.; Pinto, C.; Kara, E. +5 more
Hercules X-1 is a nearly edge-on X-ray binary with a warped, precessing accretion disk, which manifests through a 35-day cycle of alternating High and Low flux states. This disk precession introduces a changing line of sight toward the X-ray source, through an ionized accretion disk wind. The sightline variation allows us to uniquely determine how…
A Broad-line Quasar with Unexplained Extreme Velocity Offsets: Post-shock Outflow?
Schramm, Malte; Mobasher, Bahram; Steinhardt, Charles L. +4 more
The quasar SDSS 0956 + 5128 exhibits three distinct velocity components with large offsets in emission: the systemic velocity of [O II], [O III], and [Ne III] narrow lines have redshift z = 0.7142; the broad Mg II line is shifted by -1200 km s-1 with respect to the narrow lines; the broad Hα and Hβ lines are at -4100 km s-1. …
Strong Variability in AzV 493, an Extreme Oe-type Star in the SMC
Oey, M. S.; Renzo, M.; Castro, N. +11 more
We present 18 yr of OGLE photometry together with spectra obtained over 12 yr revealing that the early Oe star AzV 493 shows strong photometric (ΔI < 1.2 mag) and spectroscopic variability with a dominant, 14.6 yr pattern and ~40 day oscillations. We estimate the stellar parameters T eff = 42,000 K, $\mathrm{log}L/{L}_{\odot }=5.83\p…
A Search for X-Ray/UV Correlation in the Reflection-dominated Seyfert 1 Galaxy Markarian 1044
Jithesh, V.; Medhi, Biman J.; Misra, Ranjeev +3 more
Correlated variability between coronal X-rays and disk optical/UV photons provides a very useful diagnostic of the interplay between the different regions around an active galactic nucleus (AGN) and how they interact. AGNs that reveal strong X-ray reflection in their spectra should normally exhibit optical/UV to X-ray correlation consistent with r…
Atmospheric Pressure and Molecular Cloud Formation in Early-type Galaxies
McNamara, B. R.; Russell, H. R.; Edge, A. C. +3 more
A strong correlation between atmospheric pressure and molecular gas mass is found in central cluster galaxies and early-type galaxies. This trend and a similar trend with atmospheric gas density would naturally arise if the molecular clouds condensed from hot atmospheres. Limits on the ratio of molecular to atomic hydrogen in these systems exceed …
Transverse Vertical Oscillations During the Contraction and Expansion of Coronal Loops
Li, Qiao; Zhang, Qingmin; Li, Chuan +5 more
In this paper, we carry out a detailed analysis of the M1.6 class eruptive flare occurring in NOAA active region 13078 on 2022 August 19. The flare is associated with a fast coronal mass ejection (CME) propagating in the southwest direction with an apparent speed of ~926 km s-1. Meanwhile, a shock wave is driven by the CME at the flank.…