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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…
Study of chemically peculiar stars - I. High-resolution spectroscopy and K2 photometry of Am stars in the region of M44
Bhatt, B. C.; García, R. A.; Lund, M. N. +30 more
We present a study based on the high-resolution spectroscopy and K2 space photometry of five chemically peculiar stars in the region of the open cluster M44. The analysis of the high-precision photometric K2 data reveals that the light variations in HD 73045 and HD 76310 are rotational in nature and caused by spots or cloud-like co-rotating struct…
Models of metal-poor stars with different initial abundances of C, N, O, Mg, and Si - I. Bolometric corrections derived from new MARCS synthetic spectra and their implications for observed colour-magnitude diagrams
Casagrande, Luca; Edvardsson, Bengt; VandenBerg, Don A. +1 more
New, high-resolution MARCS synthetic spectra have been calculated for more than a dozen mixtures of the metals allowing, in turn, for variations in C:N:O, [CNO/Fe], and enhanced abundances of C, O, Mg, and Si. Bolometric corrections (BCs) for many of the broad-band filters currently in use have been generated from these spectra. Due to improved tr…
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…
Comparing the super-Eddington accretion of SMC X-3 and RX J0209.6-7427 with Swift J0243.6+6124
Weng, Shan-Shan; Liu, Jiren; Vasilopoulos, Georgios +4 more
We study the giant outbursts of SMC X-3 and RX J0209.6-7427 (hereafter RX J0209) to compare their super-Eddington accretion regime with that of Swift J0243.6+6124 (hereafter Swift J0243). The high double-peak profile of SMC X-3 is found to be 0.25 phase offset from that below 2.3 × 1038 erg s-1, which is similar to Swift J024…
Discovery of extreme, roughly daily superflares on the recurrent nova V2487 Oph
Schaefer, Bradley E.; Pagnotta, Ashley; Zoppelt, Seth
V2487 Oph is a recurrent nova with detected eruptions in 1900 and 1998. Startlingly, V2487 Oph shows flares, called 'Superflares', with up to 1.10 mag amplitude, fast rises of under one-minute, always with an initial impulsive spike followed by a roughly exponential tail, typically one-hour durations, and with random event times averaging once-per…
A spectroscopic follow-up for Gaia19bld
Gromadzki, M.; Rybicki, K.; Kruszyńska, K. +11 more
Context. Due to their scarcity, microlensing events in the Galactic disk are of great interest and high-cadence photometric observations, supplemented by spectroscopic follow-up, are necessary for constraining the physical parameters of the lensing system. In particular, a precise estimate of the source characteristics is required to accurately me…
Post maximum light and late time optical imaging polarimetry of type I superluminous supernova 2020znr
Pérez-Fournon, I.; Poidevin, F.; Omand, C. M. B. +5 more
Optical imaging polarimetry was conducted on the hydrogen poor superluminous supernova 2020znr during three phases after maximum light (≈ +34 d, +288 d, and +289 d). After instrumental and interstellar polarization correction, all measurements are consistent with null-polarization detection. Modelling the light curve with a magnetar spin-down mode…
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…