Search Publications
New Insights into the Formation of the Blue Main Sequence in NGC 1850
Milone, Antonino P.; Deng, Licai; de Grijs, Richard +2 more
Recent discoveries of bimodal main sequences (MSs) associated with young clusters (with ages ≲1 Gyr) in the Magellanic Clouds have drawn a lot of attention. One of the prevailing formation scenarios attributes these split MSs to a bimodal distribution in stellar rotation rates, with most stars belonging to a rapidly rotating population. In this sc…
Energy conversion through mass loading of escaping ionospheric ions for different Kp values
Slapak, Rikard; Yamauchi, Masatoshi
By conserving momentum during the mixing of fast solar wind flow and slow planetary ion flow in an inelastic way, mass loading converts kinetic energy to other forms - e.g. first to electrical energy through charge separation and then to thermal energy (randomness) through gyromotion of the newly born cold ions for the comet and Mars cases. Here, …
The big lobe of 67P/Churyumov-Gerasimenko comet: morphological and spectrophotometric evidences of layering as from OSIRIS data
Jorda, L.; Lamy, P. L.; Lara, L. M. +45 more
Between 2014 and 2016, ESA's Rosetta OSIRIS cameras acquired multiple-filters images of the layered nucleus of comet 67P/Churyumov-Gerasimenko, ranging from ultraviolet to near-infrared wavelengths. No correlation between layers disposition and surface spectral variegation has been observed so far. This paper investigates possible spectral differe…
A Study of Two Dwarf Irregular Galaxies with Asymmetrical Star Formation Distributions
Gouliermis, Dimitrios A.; Grebel, Eva K.; Calzetti, Daniela +23 more
Two dwarf irregular galaxies, DDO 187 and NGC 3738, exhibit a striking pattern of star formation: intense star formation is taking place in a large region occupying roughly half of the inner part of the optical galaxy. We use data on the H I distribution and kinematics and stellar images and colors to examine the properties of the environment in t…
The Seahorse Nebula: New views of the filamentary infrared dark cloud G304.74+01.32 from SABOCA, Herschel, and WISE
Miettinen, O.
Context. Filamentary molecular clouds, such as many of the infrared dark clouds (IRDCs), can undergo hierarchical fragmentation into substructures (clumps and cores) that can eventually collapse to form stars.
Aims: We aim to determine the occurrence of fragmentation into cores in the clumps of the filamentary IRDC G304.74+01.32 (hereafter, G…
A faint outburst of the accreting millisecond X-ray pulsar SAX J1748.9-2021 in NGC 6440
Mereghetti, S.; Sanna, A.; Di Salvo, T. +6 more
SAX J1748.9-2021 is an accreting X-ray millisecond pulsar observed in outburst five times since its discovery in 1998. In early October 2017, the source started its sixth outburst, which lasted only ∼13 days, significantly shorter than the typical 30 days duration of the previous outbursts. It reached a 0.3-70 keV unabsorbed peak luminosity of ∼3 …
Discovery of X-Rays from the Old and Faint Pulsar J1154-6250
Mereghetti, Sandro; Igoshev, Andrei P.; Popov, Sergei B. +4 more
We report on the first X-ray observation of the 0.28 s isolated radio pulsar PSR J1154-6250 obtained with the XMM-Newton observatory in 2018 February. A point-like source is firmly detected at a position consistent with that of PSR J1154-6250. The two closest stars are outside the 3σ confidence limits of the source position and thus unlikely to be…
Revealing the Host Galaxy of a Quasar 2175 Å Dust Absorber at z = 2.12
Ge, Jian; Prochaska, J. Xavier; Brammer, Gabriel +2 more
We report the first detection of the host galaxy of a strong 2175 Å dust absorber at z = 2.12 toward the background quasar SDSS J121143.42+083349.7 using Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3) IR F140W direct imaging and G141 grism spectroscopy. The spectroscopically confirmed host galaxy is located at a small impact parameter of ∼5…
Period Analysis, Roche Modeling and Absolute Parameters for AU Ser, an Overcontact Binary System
Alton, K. B.; Nelson, R. H.; Terrell, D.
CCD photometric data collected at UnderOak Observatory (UO) and Desert Bloom Observatory (DBO) in three bandpasses (B, V and I_C) produced 10 new times of minimum for AU Ser which were used to revise the linear ephemeris. These results captured in 2011 and 2018 reinforced a longstanding observation that the shape of the light curve from this W UMa…
Physical properties and optical-infrared transmission spectrum of the giant planet XO-1 b
Smith, A. M. S.; Mancini, L.; Madhusudhan, N. +3 more
We present 10 high-precision light curves of four transits in the XO-1 planetary system, obtained using u, g, r, redshifted H α, I, and z filters. We use these to measure the physical properties, orbital ephemeris, and a transmission spectrum of the planet covering the full optical wavelength range. We augment this with published HST/WFC3 observat…