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High-Cadence Observations of Magnetic Field Dynamics and Photospheric Emission Sources in the Eruptive Near-the-Limb X4.9 Solar Flare on 25 February, 2014: Evidences for Two-Stage Magnetic Reconnection during the Impulsive Phase
Zimovets, I. V.; Sharykin, I. N.; Radivon, A. V.
We present an analysis of the pre-limb eruptive X4.9 solar flare on February 25, 2014, by means of which we confirm a hypothesis of the two-stage energy release corresponding to two magnetic reconnection regimes in the flare impulsive phase. This flare is selected, firstly, because of its morphological peculiarities suggesting the presence of the …
Radiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809
Ebisawa, Ken; Mizumoto, Misaki; Midooka, Takuya
Recent radiation-magnetohydrodynamic simulations of active galactic nuclei predict the presence of the disk winds, which may become unstable and turn into fragmented clumps far from the central black hole. These inner winds and the outer clumps may be observed as ultrafast outflows (UFOs) and partial absorbers, respectively. However, it is challen…
Coronal voids and their magnetic nature
Schmidt, W.; Woch, J.; Barczynski, K. +68 more
Context. Extreme ultraviolet (EUV) observations of the quiet solar atmosphere reveal extended regions of weak emission compared to the ambient quiescent corona. The magnetic nature of these coronal features is not well understood.
Aims: We study the magnetic properties of the weakly emitting extended regions, which we name coronal voids. In p…
Identification of Ammonium Salts on Comet 67P/C-G Surface from Infrared VIRTIS/Rosetta Data Based on Laboratory Experiments. Implications and Perspectives
Longobardo, Andrea; Palomba, Ernesto; Schmitt, Bernard +29 more
The nucleus of comet 67P/Churyumov-Gerasimenko exhibits a broad spectral reflectance feature around 3.2 µm, which is omnipresent in all spectra of the surface, and whose attribution has remained elusive since its discovery. Based on laboratory experiments, we have shown that most of this absorption feature is due to ammonium (NH4+<…
Analysis of Solar-like X-class Flare on Wolf 359 Observed Simultaneously with TESS and XMM-Newton
Siarkowski, M.; Falewicz, R.; Bicz, K. +3 more
We present an analysis of a flare on the Wolf 359 star based on simultaneous observations of Transiting Exoplanet Survey Satellite and XMM-Newton. A stellar flare with energy comparable to an X-class solar flare is analyzed on this star for the first time. The main goal of the study was to determine whether the same physical processes drive and oc…
No random transits in CHEOPS observations of HD 139139
Guterman, P.; Alonso, R.; Deleuil, M. +77 more
Context. The star HD 139139 (a.k.a. `the Random Transiter') is a star that exhibited enigmatic transit-like features with no apparent periodicity in K2 data. The shallow depth of the events (~200 ppm - equivalent to transiting objects with radii of ~1.5 R⊕ in front of a Sun-like star) and their non-periodicity constitute a challenge for…
The Significance of Thermally Pulsing Asymptotic Giant Branch Stars in Post-starburst Galaxies
Luo, A. -Li; Liu, Siqi
We measure the significance of thermally pulsing asymptotic giant branch (TP-AGB) stars via the spectral energy distributions (SEDs) of a sample of post-starburst (PSB) galaxies at z = 0.2-0.7. Using ground- and space-based photometry from the 3D-HST catalog, as well as associated near-infrared (NIR) Hubble Space Telescope (HST) slitless grism spe…
A Reinforcement Learning-Based Follow-up Framework
Astudillo, Javiera; Protopapas, Pavlos; Pichara, Karim +1 more
Classification and characterization of variable and transient phenomena are critical for astrophysics and cosmology. Given the volume of nightly data produced by ongoing and future surveys such as LSST, it is critical to develop automatic tools that assist in observation decision-making, maximizing scientific output without resource wastage. We pr…
A Gaia based analysis of open cluster Berkeley 27
Bisht, D.; Yadav, R. K. S.; Rangwal, G. +2 more
In this paper, we have used the Gaia's Data Release-3 (DR3) data to study an intermediate-age open cluster Berkeley 27 (Be 27). A total of 131 most probable cluster members are picked within the cluster's radius based on the membership probability (> 80%). The cluster's radius was estimated as 3.74 arcmin. The mean proper motion (PM) of Be 27 w…
HI line analysis of Herbig Ae/Be stars using X-Shooter spectra
Arun, R.; Mathew, Blesson; Shridharan, B. +1 more
Herbig Ae/Be stars are intermediate-mass pre-main sequence stars undergoing accretion through their circumstellar disk. The optical and infrared (IR) spectra of HAeBe stars show HI emission lines belonging to Balmer, Paschen and Brackett series. We used the archival X-Shooter spectra available for 109 HAeBe stars from Vioque et al. (2018) and anal…