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SRG/eROSITA survey of Be stars
Nazé, Yaël; Robrade, Jan
Massive stars are known X-ray emitters and those belonging to the Be category are no exception. One type of X-ray emission even appears specific to that category, the γ Cas phenomenon. Its actual incidence has been particularly difficult to assess. Thanks to four semesters of sky survey data taken by the Spectrum-Roentgen-Gamma (SRG)/extended ROen…
Grantecan spectroscopic observations and confirmations of planetary nebulae candidates in the Northern Galactic Plane
Ritter, Andreas; Sabin, L.; Parker, Q. A. +3 more
We present Gran Telescopio Canarias (GTC) spectroscopic confirmations of 55 faint Planetary Nebulae (PNe) candidates discovered largely in the INT Photometric H α Survey (IPHAS) of the Northern Galactic Plane by our pro-am collaboration. We confirm 46 of them as 'True' (T), 4 as 'Likely' (L), and 5 as 'Possible' (P) PNe and including 5 new PNe cen…
Reeling in the Whirlpool galaxy: Distance to M 51 clarified through Cepheids and the type IIP supernova 2005cs
Leibundgut, B.; Anderson, R. I.; Blondin, S. +4 more
Context. The distance to the Whirlpool galaxy, M 51, is still debated, even though the galaxy has been studied in great detail. Current estimates range from 6.02 to 9.09 Mpc, and different methods yield discrepant results. No Cepheid distance has been published for M 51 to date.
Aims: We aim to estimate a more reliable distance to M 51 throug…
Surface chemical composition of single WNh stars
Martins, Fabrice
Context. Wolf-Rayet (WR) stars of the WNh category contain a significant fraction of hydrogen at their surface. They can be hydrogen-burning, very massive stars or stars in a post-main sequence phase of evolution. Also, WNh stars are sometimes not included in population synthesis models.
Aims: We aim to better characterise the properties of s…
The Disturbed and Globular-cluster-rich Ultradiffuse Galaxy UGC 9050-Dw1
Sand, David J.; Jones, Michael G.; Fielder, Catherine E. +5 more
We investigate the ultradiffuse galaxy (UDG) UGC 9050-Dw1, which was selected because of its disturbed morphology as part of a larger sample of UDGs that display evidence for significant interactions. We use the Hubble Space Telescope's Advanced Camera for Surveys to identify globular clusters (GCs) associated with UGC 9050-Dw1, and the Jansky Ver…
On the Relation Between Jupiter's Aurora and the Dawnside Current Sheet
Wei, Y.; Delamere, P. A.; Badman, S. V. +10 more
Jupiter's auroral emission is a spectacular phenomenon that provides insight into energy release processes related to the coupling of its magnetosphere and ionosphere. This energy release is influenced by solar wind conditions. Using joint observations from Juno and the Hubble Space Telescope (HST), we statistically investigate the relationship be…
Accurate mass-radius ratios for Hyades white dwarfs
Salaris, M.; Pasquini, L.; Pala, A. F. +4 more
We use the ESPRESSO spectrograph at the Very Large Telescope to measure velocity shifts and gravitational redshifts of eight bona fide Hyades white dwarfs, with an accuracy better than 1.5 per cent. By comparing the gravitational redshift measurements of the mass-to-radius ratio with the same ratios derived by fitting the Gaia photometry with theo…
Catalog of the Galactic Population of X-Ray Pulsars in High-mass X-Ray Binary Systems
Kim, Vitaliy; Izmailova, Ildana; Aimuratov, Yerlan
A catalog of the Galactic population of X-ray pulsars in high-mass X-ray binary (HMXB) systems is presented. It contains information about 82 confirmed sources: 18 persistent and 64 transient pulsars. Their basic parameters include spin period, spin evolution with global and local spin-up/spin-down and duration, orbital period, X-ray luminosity, m…
Relationships between energetic storm particle events and interplanetary shocks driven by full and partial halo coronal mass ejections
Vainio, Rami; Valtonen, Eino; Al-Sawad, Amjad +1 more
We have analysed energetic storm particle (ESP) events in 116 interplanetary (IP) shocks driven by front-side full and partial halo coronal mass ejections (CMEs) with speeds > 400 km s-1during the years 1996-2015. We investigated the occurrence and relationships of ESP events with several parameters describing the IP shocks, and the …
An emerging and enigmatic spectral class of isolated DAe white dwarfs
Hermes, J. J.; Munday, James; Gänsicke, Boris T. +9 more
Two recently discovered white dwarfs, WD J041246.84 + 754942.26 and WD J165335.21 - 100116.33, exhibit Hα and Hβ Balmer line emission similar to stars in the emerging DAHe class, yet intriguingly have not been found to have detectable magnetic fields. These white dwarfs are assigned the spectral type DAe. We present detailed follow-up of the two k…