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Observations of compact sources in galaxy clusters using MUSTANG2
Sarazin, Craig L.; Hilton, Matt; Sifón, Cristóbal +26 more
Compact sources can cause scatter in the scaling relationships between the amplitude of the thermal Sunyaev-Zel'dovich Effect (tSZE) in galaxy clusters and cluster mass. Estimates of the importance of this scatter vary - largely due to limited data on sources in clusters at the frequencies at which tSZE cluster surveys operate. In this paper, we p…
New X-ray observations of the hot subdwarf binary HD 49798/RX J0648.0-4418
Rauch, T.; Tiengo, A.; Mereghetti, S. +7 more
HD 49798/RX J0648.0-4418 is the only confirmed X-ray binary in which the mass donor is a hot subdwarf star of O spectral type and, most likely, it contains a massive white dwarf (1.28 ± 0.05 M⊙) with a very fast spin period of 13.2 s. Here, we report the results of new XMM-Newton pointings of this peculiar binary, carried out in 2018 an…
Extreme relativistic reflection in the active galaxy ESO 033-G002
Harrison, F. A.; Stern, D.; Fabian, A. C. +13 more
We present the first high signal-to-noise broad-band X-ray spectrum of the radio-quiet type-2 Seyfert ESO 033-G002, combining data from XMM-Newton and NuSTAR. The nuclear X-ray spectrum is complex, showing evidence for both neutral and ionized absorption, as well as reflection from both the accretion disc and more distant material, but our broad-b…
Detection of millihertz quasi-periodic oscillations in the X-Ray binary 1RXS J180408.9-342058
Galloway, Duncan K.; Chou, Yi; Hsieh, Hung-En +2 more
Millihertz quasi-periodic oscillations (mHz QPOs) observed in neutron-star low-mass X-ray binaries (NS LMXBs) are generally explained as marginally stable thermonuclear burning on the neutron star surface. We report the discovery of mHz QPOs in an XMM-Newton observation of the transient 1RXS J180408.9-342058, during a regular bursting phase of its…
Photometric and Kinematic Study of the Open Clusters SAI 44 and SAI 45
Sharma, Saurabh; Joshi, Y. C.; Elsanhoury, W. H. +1 more
We carry out a detailed photometric and kinematic study of the poorly studied sparse open clusters SAI 44 and SAI 45 using ground-based BVRcIc data supplemented by archival data from Gaia eDR3 and Pan-STARRS. The stellar memberships are determined using a statistical method based on Gaia eDR3 kinematic data, and we found 204 …
The Source Locations of Major Flares and CMEs in Emerging Active Regions
Wang, Yuming; Liu, Lijuan; Cui, Jun +1 more
Major flares and coronal mass ejections (CMEs) tend to originate from compact polarity inversion lines (PILs) in solar active regions (ARs). Recently, a scenario named "collisional shearing" was proposed by Chintzoglou et al. to explain the phenomenon, which suggests that the collision between different emerging bipoles is able to form a compact P…
AlFoCS + F3D - II. Unexpectedly low gas-to-dust ratios in the Fornax galaxy cluster
De Looze, Ilse; Baes, Maarten; Bendo, George J. +14 more
We combine observations from Atacama Large Millimeter/submillimeter Array (ALMA), Australia Telescope Compact Array, Multi Unit Spectroscopic Explorer (MUSE), and Herschel to study gas-to-dust ratios in 15 Fornax cluster galaxies detected in the FIR/sub-mm by Herschel and observed by ALMA as part of the ALMA Fornax Cluster Survey. The sample spans…
APOGEE-2S Discovery of Light- and Heavy-element Abundance Correlations in the Bulge Globular Cluster NGC 6380
Cunha, Katia; Smith, Verne V.; Majewski, Steven R. +11 more
We derive abundance ratios for nine stars in the relatively high-metallicity bulge globular cluster NGC 6380. We find a mean cluster metallicity between [Fe/H] = -0.80 and -0.73, with no clear evidence for a variation in iron abundances beyond the observational errors. Stars with strongly enhanced [N/Fe] abundance ratios populate the cluster and a…
Mrk 1239: a Type-2 Counterpart of Narrow-line Seyfert-1?
Zhou, Hongyan; Ji, Tuo; Shi, Xiheng +10 more
We present new spectrophotometric and spectropolarimetric observations of Mrk 1239, one of the 8 prototypes that defines type-1 narrow-line Seyfert galaxies (NLS1s). Unlike the other typical NLS1s though, a high degree of polarization (P ∼ 5.6%) and red optical-IR (g-W4 = 12.35) colors suggest that Mrk 1239 is more similar to type-2 act…
Looking into the cradle of the grave: J22564-5910, a potential young post-merger hot subdwarf
Uzundag, Murat; Pelisoli, Ingrid; Bobrick, Alexey +10 more
Context. We present the discovery of J22564-5910, a new type of hot subdwarf (sdB) which shows evidence of gas present in the system and it has shallow, multi-peaked hydrogen and helium lines which vary in shape over time. All observational evidence points towards J22564-5910 being observed very shortly after the merger phase that formed it.
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