Search Publications
AWSoM Magnetohydrodynamic Simulation of a Solar Active Region with Realistic Spectral Synthesis
Landi, Enrico; van der Holst, Bart; Szente, Judit +6 more
For the first time, we simulate the detailed spectral line emission from a solar active region (AR) with the Alfvén Wave Solar Model (AWSoM). We select an AR appearing near disk center on 2018 July 13 and use the National Solar Observatory's Helioseismic and Magnetic Imager synoptic magnetogram to specify the magnetic field at the model's inner bo…
First Laboratory Measurement of Magnetic-field-induced Transition Effect in Fe X at Different Magnetic Fields
Tian, Hui; Bai, Xianyong; Si, Ran +14 more
The magnetic field is extremely important for understanding the properties of the solar corona. However, there are still difficulties in the direct measurement of the coronal magnetic field. The magnetic-field-induced transition (MIT) in Fe X, appearing in coronal spectra, was discovered to have prospective applications in coronal magnetic field m…
Searching for the Signal of a Primordial Black Hole from CMB Lensing and γ-Ray Emissions
Qiu, Taotao; Tan, Xiu-Hui; Xia, Jun-Qing +1 more
In this letter, we search for the signal of primordial black holes (PBHs) by correlating the γ-ray emissions in the MeV energy band produced by the Hawking evaporation and the lensing effect of the cosmic microwave background (CMB). We use the conservative case of the astrophysical model as much as possible in the calculations, since the potential…
Beyond the Local Volume. II. Population Scaleheights and Ages of Ultracool Dwarfs in Deep HST/WFC3 Parallel Fields
Holwerda, Benne; Burgasser, Adam J.; Ryan, Russell E. +6 more
Ultracool dwarfs (UCDs) represent a significant proportion of stars in the Milky Way, and deep samples of these sources have the potential to constrain the formation history and evolution of low-mass objects in the Galaxy. Until recently, spectral samples have been limited to the local volume (d < 100 pc). Here, we analyze a sample of 164 spect…
The Extremely Buried Nucleus of IRAS 17208-0014 Observed at Submillimeter and Near-infrared Wavelengths
Onishi, Shusuke; Nakagawa, Takao; Baba, Shunsuke +6 more
The ultraluminous infrared galaxy IRAS 17208-0014 is a late-stage merger that hosts a buried active galactic nucleus (AGN). To investigate its nuclear structure, we performed high-spatial-resolution ( ~ 0.″04 ~ 32 pc) Atacama Large Millimeter/submillimeter Array (ALMA) observations in Band 9 (~450 µm or ~660 GHz), along with near-infrared AK…
Deblending Galaxies with Generative Adversarial Networks
Mobasher, Bahram; Rhodes, Jason; Hemmati, Shoubaneh +6 more
Deep generative models including generative adversarial networks (GANs) are powerful unsupervised tools in learning the distributions of data sets. Building a simple GAN architecture in PyTorch and training on the CANDELS data set, we generate galaxy images with the Hubble Space Telescope (HST) resolution starting from a noise vector. We proceed b…
Shocks in the Outflow of the RS Oph 2021 Eruption Observed with X-Ray Gratings
Luna, G. J. M.; Della Valle, M.; Behar, E. +9 more
The 2021 outburst of the symbiotic recurrent nova RS Oph was observed with the Chandra High Energy Transmission Gratings (HETG) on day 18 after optical maximum and with XMM-Newton and its Reflection Grating Spectrographs (RGS) on day 21, before the supersoft X-ray source emerged and when the emission was due to shocked ejecta. The absorbed flux in…
What Determines Active Region Coronal Plasma Composition?
Long, David M.; Brooks, David H.; Baker, Deborah +4 more
The chemical composition of the solar corona is different from that of the solar photosphere, with the strongest variation being observed in active regions (ARs). Using data from the Extreme Ultraviolet (EUV) Imaging Spectrometer (EIS) on Hinode, we present a survey of coronal elemental composition as expressed in the first ionization potential (F…
Decoding the X-Ray Flare from MAXI J0709-159 Using Optical Spectroscopy and Multiepoch Photometry
Arun, R.; Mathew, Blesson; Kartha, Sreeja S. +10 more
We present a follow-up study on the recent detection of two X-ray flaring events by MAXI/Gas Slit Camera observations in soft and hard X-rays from MAXI J0709-159 in the direction of HD 54786 (LY CMa), on 2022 January 25. The X-ray luminosity during the flare was around 1037 erg s-1 (MAXI), which got reduced to 1032…
HST Observations of the Globular Cluster NGC 6402 (M14) and Its Peculiar Multiple Populations
D'Antona, Francesca; Milone, Antonino P.; Tailo, Marco +6 more
We present Hubble Space Telescope (HST) photometric results for NGC 6402, a highly reddened, very luminous Galactic globular cluster (GC). Recent spectroscopic observations of its red giant stars have shown a quite peculiar behavior in the chemistry of its multiple populations. These results have prompted UV and optical HST observations aimed at o…