Search Publications
The GALAH survey: velocity fluctuations in the Milky Way using Red Clump giants
Lewis, Geraint F.; Ting, Yuan-Sen; Wittenmyer, Robert A. +20 more
If the Galaxy is axisymmetric and in dynamical equilibrium, we expect negligible fluctuations in the residual line-of-sight velocity field. Recent results using the APOGEE survey find significant fluctuations in velocity for stars in the mid-plane (|z| <0.25 kpc) out to 5 kpc, suggesting that the dynamical influence of non-axisymmetric features…
Rest-frame UV and optical emission line diagnostics of ionized gas properties: a test case in a star-forming knot of a lensed galaxy at z ∼ 1.7
Kewley, Lisa J.; Blanc, Guillermo A.; Acharyya, Ayan +7 more
We examine the diagnostic power of rest-frame ultraviolet (UV) nebular emission lines, and compare them to more commonly used rest-frame optical emission lines, using the test case of a single star-forming knot of the bright lensed galaxy RCSGA 032727-132609 at redshift z ∼ 1.7. This galaxy has complete coverage of all the major rest-frame UV and …
A newly discovered double-double candidate microquasar in NGC 300
Maccarone, T. J.; Motch, C.; Scaringi, S. +7 more
We present the discovery of a powerful candidate microquasar in NGC 300, associated with the S 10 optical nebula (previously classified as a supernova remnant). Chandra images show four discrete X-ray knots aligned in the plane of the sky over a length of ≈150 pc. The X-ray emission from the knots is well fitted with a thermal plasma model at a te…
A short and sudden increase of the magnetic field strength and the accompanying spectral variability in the O9.7 V star HD 54879
Hubrig, S.; Schöller, M.; Järvinen, S. P. +4 more
Only 11 O-type stars have been confirmed to possess large-scale organized magnetic fields. The presence of a -600 G longitudinal magnetic field in the O9.7 V star HD 54879 with a lower limit of the dipole strength of ∼2 kG was discovered a few years ago in the framework of the ESO large program `B-fields in OB stars'. Our FORS 2 spectropolarimetri…
A remarkable change of the spectrum of the magnetic Of?p star HD 148937 reveals evidence of an eccentric, high-mass binary
Howarth, I. D.; Wade, G. A.; Gamen, R. +10 more
We report new spectroscopic observations of the magnetic Of?p star HD 148937 obtained since 2015 that differ qualitatively from its extensive historical record of weak, periodic spectral variations. This remarkable behaviour represents clear evidence for an unprecedented change in the character of variability of the star. In this paper, we describ…
Identifications of faint Chandra sources in the globular cluster M3
Heinke, Craig O.; Cool, Adrienne M.; Zhao, Yue +2 more
We report a 30 ksChandra ACIS-S survey of the globular cluster M3. Sixteen X-ray sources were detected within the half-light radius (2.3 arcmin) with L_X ≳ 2.3 × 10^{31} erg s^{-1}. We used Hubble Space Telescope WFC3/UVIS and ACS/WFC images to find 10 plausible optical/UV counterparts. We fit the spectral energy distribution of the known cataclys…
PoGO+ polarimetric constraint on the synchrotron jet emission of Cygnus X-1
Takahashi, Hiromitsu; Uchida, Nagomi; Kataoka, Jun +8 more
We report a polarimetric constraint on the hard X-ray synchrotron jet emission from the Cygnus X-1 black hole binary system. The observational data were obtained using the PoGO+ hard X-ray polarimeter in 2016 July, when Cygnus X-1 was in the hard state. We have previously reported that emission from an extended corona with a low polarization fract…
The retrograde orbit of the globular cluster FSR1758 revealed with Gaia DR2
Simpson, Jeffrey D.
We report the first radial velocity measurements of the recently identified globular cluster FSR1758. From the two member stars with radial velocities from the Gaia Radial Velocity Spectrograph reported in Gaia DR2, we find FSR1758 has a radial velocity of 227 ± 1 km s^{-1}. We also find potential extra-tidal star lost from the cluster in the surr…
The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy PKS J1222+0413
Done, Chris; Angelakis, Emmanouil; Landt, Hermine +6 more
We present a multifrequency study of PKS J1222+0413 (4C +04.42), currently the highest redshift γ-ray emitting narrow-line Seyfert 1 (γ-NLS1). We assemble a broad spectral energy distribution (SED) including previously unpublished datasets: X-ray data obtained with the NuSTAR and Neil Gehrels Swift observatories; near-infrared, optical, and UV spe…
The mid-infrared and CO gas properties of an extreme star-forming FeLoBAL quasar
Lacy, Mark; Hatziminaoglou, Evanthia; Afonso, José +6 more
We present a detailed study of a high-redshift iron low-ionization broad absorption line (FeLoBAL) quasar (SDSS1214 at z = 1.046), including new interferometric 12CO J = 2-1 observations, optical through far-infrared photometry, and mid-infrared spectroscopy. The CO line is well fit by a single Gaussian centred 40 km s-1 away…