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Vertical distribution of HMXBs in NGC 55: constraining their centre-of-mass velocity
Zezas, Andreas; Williams, Stephen J.; Andrews, Jeff J. +1 more
We analyse the vertical distribution of high-mass X-ray binaries (HMXBs) in NGC 55, the nearest edge-on galaxy to the Milky Way (MW), based on X-ray observations by Chandra. Adopting a statistical approach, we estimate the difference between the scale height of the vertical distribution of HMXBs and the vertical distribution of star-forming activi…
Feasibility of Observing Gamma-Ray Polarization from Cygnus X-1 Using a CubeSat
Chang, Hsiang-Kuang; Laurent, Philippe; Rodriguez, Jerome +7 more
Instruments flown on CubeSats are small. Meaningful applications of CubeSats in astronomical observations rely on the choice of a particular subject that is feasible for CubeSats. Here we report the result of a feasibility study for observing gamma-ray polarization from Cygnus X-1 using a small Compton polarimeter on board a 3U CubeSat. Silicon de…
Two-epoch Orbit Estimation for Wide Binaries Resolved in Hipparcos and Gaia
Makarov, Valeri V.
The Hipparcos catalog and its Double and Multiple System Annex (DMSA) lists 4099 components with individual proper motions and coordinates on the epoch 1991.25. Many of these long-period binary stars are also present in Gaia Data Release 2 (DR2). Using the available relative positions and proper motions separated by 24.25 yr, the equations of rela…
A study on the dynamic spectral indices for SEP events on 2000 July 14 and 2005 January 20
Le, Gui-Ming; Zhao, Ming-Xian
We have studied the dynamic proton spectra for the two solar energetic particle (SEP) events on 2000 July 14 (hereafter GLE59) and 2005 January 20 (hereafter GLE69). The source locations of GLE59 and GLE69 are N22W07 and N12W58 respectively. Proton fluxes >30 MeV have been used to compute the dynamic spectral indices of the two SEP events. Our …
A Lyα nebula at z ∼ 3.3
Thomas, R.; Hibon, P.; Tang, F.
Context. Searching for high-redshift galaxies is a field of intense activity in modern observational cosmology that will continue to grow with future ground-based and sky observatories. Over the last few years, a lot has been learned about the high-z Universe.
Aims: Despite extensive Lyα blobs (LAB) surveys from low to high redshifts, giant L…
The Complex Rotational Light Curve of (385446) Manwë-Thorondor, a Multicomponent Eclipsing System in the Kuiper Belt
Verbiscer, Anne J.; Grundy, William M.; Thirouin, Audrey +2 more
Kuiper Belt Object (385446) Manwë-Thorondor is a multiobject system with mutual events predicted to occur from 2014 to 2019. To detect the events, we observed the system at 4 epochs (UT 2016 August 25 and 26, 2017 July 22 and 25, 2017 November 9, and 2018 October 6) in g, r, and VR bands using the 4 m SOAR and the 8.1 m Gemini South telescopes at …
The Zelima asteroid family: Resonant configuration and rotational fission clusters
Carruba, V.; Ribeiro, J. V.
Asteroid families are groups of asteroids that are identifiable in domains of proper elements. They may be the outcome of a collision, or the product of rotational fission. Among collisional families, young asteroid families are of interest because they preserve information on the original ejection velocity field with which the asteroid fragments …
Solar modulation of the GCR flux and dose rate, observed in space between 1991 and 2019
Dachev, Tsvetan P.; Tomov, Borislav T.; Matviichuk, Yuri N. +7 more
The paper presents the solar modulation of the long-term galactic cosmic rays (GCR) flux and dose rates variations, observed during 14 space experiments by 10 Bulgarian build Liulin-type spectrometers (LTS) (Dachev et al., 2015a). They worked in near Earth space and in the interplanetary radiation environment between January 1991 and January 2019.…
Dust and gas absorption in the high mass X-ray binary IGR J16318-4848
Fürst, Felix; Grinberg, Victoria; Kretschmar, Peter +11 more
Context. With an absorption column density on the order of 1024 cm-2, IGR J16318-4848 is one of the most extreme cases of a highly obscured high mass X-ray binary. In addition to the overall continuum absorption, the source spectrum exhibits a strong iron and nickel fluorescence line complex at 6.4 keV. Previous empirical mod…
Discovery of extended structures around two evolved planetary nebulae M2-55 and Abell 2
Zhang, Yong; Hsia, Chih-Hao; Zhang, Xi-Liang +1 more
We report a multi-wavelength study of two evolved planetary nebulae (PNs)M2-55 and Abell 2. Deep optical narrow-band images ([O III], Hα, and [N II]) of M2-55 reveal two pairs of bipolar lobes and a new faint arc-like structure. This arc-shaped filament around M2-55 appears as a well-defined boundary from southwest to southeast, strongly suggestin…