Search Publications
Update of membership and mean proper motion of open clusters from UCAC5 catalogue
Assafin, M.; Dias, W. S.; Monteiro, H.
We present mean proper motions and membership probabilities of individual stars for optically visible open clusters, which have been determined using data from the UCAC5 catalogue. This follows our previous studies with the UCAC2 and UCAC4 catalogues, but now using improved proper motions in the GAIA reference frame. In the present study results w…
Disc instabilities and nova eruptions in symbiotic systems: RS Ophiuchi and Z Andromedae
Hameury, J. -M.; Lasota, J. -P.; Bollimpalli, D. A.
Using the disc instability model for dwarf novae and soft X-ray transients, we investigate the stability of accretion discs in long-period binary systems. We simulate outbursts resulting from this thermal-viscous instability for two symbiotic systems, RS Ophiuchi and Z Andromedae. The outburst properties deduced from our simulations suggest that, …
The 26.3-h orbit and multiwavelength properties of the `redback' millisecond pulsar PSR J1306-40
Linares, Manuel
We present the discovery of the variable optical and X-ray counterparts to the radio millisecond pulsar (MSP) PSR J1306-40, recently discovered by Keane et al. We find that both the optical and X-ray fluxes are modulated with the same period, which allows us to measure for the first time the orbital period Porb = 1.097 16[6] d. The opti…
HST spectrum and timing of the ultracompact X-ray binary candidate 47 Tuc X9
Maccarone, T. J.; Knigge, C.; van den Berg, M. +17 more
To confirm the nature of the donor star in the ultracompact X-ray binary candidate 47 Tuc X9, we obtained optical spectra (3000-10 000 Å) with the Hubble Space Telescope / Space Telescope Imaging Spectrograph. We find no strong emission or absorption features in the spectrum of X9. In particular, we place 3σ upper limits on the H α and He II λ4686…
The straight and isolated G350.54+0.69 filament: density profile and star formation content
Liu, Hong-Li; Yuan, Jing-Hua; Stutz, Amelia
We investigate the global properties of the straight and isolated filamentary cloud G350.54+0.69 using the Herschelcontinuum and APEX molecular line data. The overall straight morphology is similar to that of two other well-studied nearby filaments (Musca and Taurus-B211/3), while the isolated nature of G350.54+0.69 appears similar to that of Musc…
Lurking systematics in predicting galaxy cold gas masses using dust luminosities and star formation rates
Janowiecki, Steven; Cortese, Luca; Goodwin, Adelle J. +1 more
We use galaxies from the Herschel Reference Survey to evaluate commonly used indirect predictors of cold gas masses. We calibrate predictions for cold neutral atomic and molecular gas using infrared dust emission and gas depletion time methods that are self-consistent and have ∼20 per cent accuracy (with the highest accuracy in the prediction of t…
The gaseous environments of quasars: associate absorption lines with density and distance constraints
Hamann, Fred; Chen, Chen; Simon, Leah +1 more
Associated absorption lines (AALs) in quasar spectra are valuable probes of the gas kinematics and physical conditions in quasar environments. The host galaxies are by definition in an active evolution stage that might involve large-scale blowouts and/or cold-mode accretion (infall) from the intergalactic medium (IGM). We discuss rest-frame UV spe…
Massive stars in the Sagittarius Dwarf Irregular Galaxy
Garcia, Miriam
Low metallicity massive stars hold the key to interpret numerous processes in the past Universe including re-ionization, starburst galaxies, high-redshift supernovae, and γ-ray bursts. The Sagittarius Dwarf Irregular Galaxy [SagDIG, 12+log(O/H) = 7.37] represents an important landmark in the quest for analogues accessible with 10-m class telescope…
Disentangling the complex broad-band X-ray spectrum of IRAS 13197-1627 with NuSTAR, XMM-Newton and Suzaku
Harrison, F. A.; Stern, D.; Fabian, A. C. +8 more
We present results from a coordinated XMM-Newton+NuSTAR observation of the type 1.8 Seyfert galaxy IRAS 13197-1627. This is a highly complex source, with strong contributions from relativistic reflection from the inner accretion disc, neutral absorption and further reprocessing by more distant material, and ionized absorption from an outflow. We u…
Joint NuSTAR and Chandra analysis of the obscured quasar in IC 2497 - Hanny's Voorwerp system
Schawinski, Kevin; Sartori, Lia F.; Gandhi, Poshak +9 more
We present new Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the core of IC 2497, the galaxy associated with Hanny's Voorwerp. The combined fits of the Chandra (0.5-8 keV) and NuSTAR (3-24 keV) X-ray spectra, together with WISE mid-IR photometry, optical longslit spectroscopy and optical narrow-band imaging, suggest that the galax…