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Spectroscopy of Candidate Members of the Sco-Cen Complex
Luhman, K. L.; Esplin, T. L.
We present spectroscopy of 285 previously identified candidate members of populations in the Sco-Cen complex, primarily Ophiuchus, Upper Sco, and Lupus. The spectra are used to measure spectral types and diagnostics of youth. We find that 269 candidates exhibit signatures of youth in our spectra or previous data, which is consistent with their mem…
Discrepancy between the Low-frequency Cutoffs of Type III Radio Bursts Based on Simultaneous Observations by WIND and PSP
Bale, Stuart D.; Pulupa, Marc; Wu, Dejin +2 more
The cutoff frequency is an important characteristic parameter of type III radio bursts. Employing the radio data of the Parker Solar Probe (PSP) in the encounter phases of its first five orbits, our previous work revealed that the maximum probability distribution of the cutoff frequency f lo (~680 kHz) is remarkably higher than that b…
The Central 300 pc of the Galaxy Probed by Infrared Spectra of H3 + and CO. III. Locations of Sgr B2 and Star Iota
Geballe, T. R.; Oka, Takeshi
Using a simple relation between the radial expansion velocity of diffuse gas in the Central Molecular Zone (CMZ) of the Galaxy and its distance from Sgr A* we estimate the physical depths within the CMZ of Star ι (2MASS J17470898-2829561) and two Sgr B2 far-infrared continuum sources with respect to the location of Sgr A*. To do this we…
Broad-band analysis of X-ray pulsar 2S 1845-024
Tsygankov, Sergey S.; Lutovinov, Alexander A.; Poutanen, Juri +4 more
We present the results of a detailed investigation of the poorly studied X-ray pulsar 2S 1845−024 based on data obtained at the NuSTAR observatory during the type I outburst in 2017. Neither pulse phase-averaged nor phase-resolved spectra of the source show evidence for a cyclotron absorption feature. We also used data obtained from other X-ray ob…
Deep V and I CCD photometry of young star cluster NGC 1893 with the 3.6m DOT
Pandey, S. B.; Panwar, Neelam; Kumar, Amit
Young star clusters consisting of massive stars are the ideal sites to study the star formation processes and influence of massive stars on the subsequent star formation. NGC 1893 is a young star cluster associated with the HII region Sh2-236. It contains about five 'O'-type stars and several early 'B'-type stars. It is located at a moderate dista…
The eROSITA extragalactic CalPV serendipitous catalog
Maitra, Chandreyee; Nandra, Kirpal; Reiprich, Thomas H. +22 more
Context. The eROSITA X-ray telescope on board the Spectrum-Roentgen-Gamma (SRG) observatory performed calibration and performance verification (CalPV) observations between September 2019 and December 2019, ahead of the planned 4-yr all-sky surveys. Most of them were deep, pointing-mode observations.
Aims: We present here the X-ray catalog det…
Unveiling the formation of NGC 2915 with MUSE: A counter-rotating stellar disk embedded in a disordered gaseous environment
Lin, Zesen; Chen, Guangwen; Kong, Xu +6 more
NGC 2915 is a unique nearby galaxy that is classified as an isolated blue compact dwarf based on its optical appearance but has an extremely extended H I gas disk with prominent Sd-type spiral arms. To unveil the starburst-triggering mystery of NGC 2915, we performed a comprehensive analysis of deep VLT/MUSE integral field spectroscopic observatio…
On the precision of full-spectrum fitting of simple stellar populations - IV. A systematic comparison with results from colour-magnitude diagrams
Goudfrooij, Paul; Asa'd, Randa; As'ad, A. M.
In this fourth paper of a series on the precision of ages of stellar populations obtained through the full-spectrum fitting technique, we present a first systematic analysis that compares the age, metallicity, and reddening of star clusters obtained from resolved and unresolved data [namely colour-magnitude diagrams (CMDs) and integrated-light spe…
Constraining leptonic emission scenarios for the PeVatron candidate HESS J1702−420 with deep XMM-Newton observations
Khélifi, B.; Lemière, A.; Terrier, R. +3 more
Aims: We aim to search for a hidden leptonic accelerator, such as a high-Ė pulsar, associated with the unidentified TeV object HESS J1702−420A.
Methods: We carried out a 72 ks X-ray observation with the XMM-Newton satellite and analyzed the resulting data jointly with the publicly available HESS spectral energy distribution (SED) results…
Photometric Investigation of Contact Binary DY Cet Based on TESS Data
Yıldırım, M. F.
We present a photometric analysis of the Transiting Exoplanet Survey Satellite (TESS) light curve of contact binary system DY Cet and the behavior of its orbital period variation. The light curve and published radial velocity data analysis was performed using the Wilson-Devinney code. As a result of simultaneous analysis of the light curve with ra…