Search Publications
Estimation of the Parameters of the Spiral Pattern in the Galaxy Based on a Sample of Classical Cepheids
Bobylev, V. V.
We consider a sample of Galactic classical Cepheids with highly accurate estimates of their distances taken from Skowron et al., where they were determined based on the period-luminosity relation. We have refined the geometric characteristics of two spiral arm segments—the Carina-Sagittarius and Outer ones. For this purpose, we have selected 269 C…
The Ages of Optically Bright Subclusters in the Serpens Star-forming Region
Fang, Min; Herczeg, Gregory J.; Liu, Yao +2 more
The Serpens Molecular Cloud is one of the most active star-forming regions within 500 pc, with over 1000 young stellar objects (YSOs) at different evolutionary stages. The ages of the member stars inform us about the star formation history of the cloud. In this paper, we develop a spectral energy distribution (SED) fitting method for nearby evolve…
Binary Clusters: Theory and Observations
Vereshchagin, S. V.; Chupina, N. V.; Tutukov, A. V. +2 more
The aim of this study is to search for close binary gravitationally bound pairs of open star clusters (CBOCs). We divided the observed pairs of clusters into visual binaries (VBOCs) and close pairs of CBOCs. Close pairs are physically bound clusters; the distances between them do not exceed 7 pc. These include pairs of clusters whose distances and…
Gamma-ray light curves and spectra of classical novae
Siegert, Thomas; Leung, Shing-Chi
The nucleosynthesis in classical novae, in particular that of radioactive isotopes, is directly measurable by its γ-ray signature. Despite decades of observations, MeV γ-rays from novae have never been detected - neither individually at the time of the explosion, nor as a result of radioactive decay, nor the diffuse Galactic emission from the nova…
A new method to correct for host star variability in multiepoch observations of exoplanet transmission spectra
Fortney, Jonathan J.; Stevenson, Kevin B.; Désert, Jean-Michel +5 more
Transmission spectra of exoplanets orbiting active stars suffer from wavelength-dependent effects due to stellar photospheric heterogeneity. WASP-19b, an ultra-hot Jupiter (Teq ~ 2100 K), is one such strongly irradiated gas-giant orbiting an active solar-type star. We present optical (520-900 nm) transmission spectra of WASP-19b obtaine…
Optical Studies of 10 Hard X-Ray-selected Cataclysmic Binaries
Thorstensen, John R.; Halpern, Jules P.
We conducted time-resolved optical spectroscopy and/or photometry of 10 cataclysmic binaries that were discovered in hard X-ray surveys, with the goal of measuring their orbital periods and searching for evidence that they are magnetic. Four of the objects in this study are new optical identifications: IGR J18017-3542, PBC J1841.1+0138, IGR J18434…
The Three Hundred project: dissecting the Fundamental Plane of galaxy clusters up to z = 1
Cui, Weiguang; Umetsu, Keiichi; Meneghetti, Massimo +2 more
We perform a systematic study of the recently discovered Fundamental Plane of galaxy clusters (CFP) using ~250 simulated clusters from The Three Hundred project, focusing on the stability of the plane against different temperature definitions and its dependence on the dynamical relaxation state of clusters. The CFP is characterized by $T\propto M_…
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…