Search Publications
The First Ultraviolet Detection of the Large Magellanic Cloud Pulsar PSR B0540-69 and Its Multi-wavelength Properties
de Luca, A.; Barbieri, C.; Naletto, G. +9 more
We observed the young (∼1700 yr) pulsar PSR B0540-69 in the ultraviolet for the first time with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. Imaging observations with the NUV-MAMA and ultraviolet FUV-MAMA detectors in TIME-TAG mode allowed us to clearly detect the pulsar in two bands around 2350 and 1590 Å, with ma…
LOFAR Discovery of a Radio Halo in the High-redshift Galaxy Cluster PSZ2 G099.86+58.45
Di Gennaro, G.; Brunetti, G.; Shimwell, T. W. +15 more
In this Letter, we report the discovery of a radio halo in the high-redshift galaxy cluster PSZ2 G099.86+58.45 (z = 0.616) with the LOw Frequency ARray (LOFAR) at 120-168 MHz. This is one of the most distant radio halos discovered so far. The diffuse emission extends over ∼1 Mpc and has a morphology similar to that of the X-ray emission as reveale…
Luminous AGB variables in the dwarf irregular galaxy, NGC 3109
Matsunaga, Noriyuki; Whitelock, Patricia A.; Feast, Michael W. +1 more
In a shallow near-infrared survey of the dwarf irregular galaxy, NGC 3109, near the periphery of the Local Group, we have found eight Mira variables, seven of which appear to be oxygen-rich (O-Miras). The periods range from about 430 d to almost 1500 d. Because of our relatively bright limiting magnitude, only 45 of the more than 400 known carbon …
Searching for intergalactic star forming regions in Stephan's Quintet with SITELLE. I. Ionised gas structures and kinematics
Kehrig, C.; Iglesias-Páramo, J.; Drissen, L. +3 more
Stephan's Quintet (SQ), the prototypical compact group of galaxies in the local Universe, has been observed with the imaging Fourier transform spectrometer SITELLE, attached to the Canada-France-Hawaii-Telescope, to perform a deep search for intergalactic star-forming emission. In this paper we present the extended ionised gaseous structures detec…
Fingerprinting the effects of hyperfine structure on CH and OH far infrared spectra using Wiener filter deconvolution
Lee, Min-Young; Menten, Karl M.; Jacob, Arshia M. +3 more
Context. Despite being a commonly observed feature, the modification of the velocity structure in spectral line profiles by hyperfine structure complicates the interpretation of spectroscopic data. This is particularly true for observations of simple molecules such as CH and OH toward the inner Galaxy, which show a great deal of velocity crowding.…
Spatially Resolved Outflows in a Seyfert Galaxy at z = 2.39
Dahle, H.; Rigby, J. R.; Sharon, K. +11 more
We present the first spatially resolved analysis of rest-frame optical and UV imaging and spectroscopy for a lensed galaxy at z = 2.39 hosting a Seyfert active galactic nucleus (AGN). Proximity to a natural guide star has enabled observations with high signal-to-noise ratio using Very Large Telescope SINFONI + adaptive optics (AO) of rest-frame op…
Accurate effective temperature from Hα profiles
Pasquini, L.; Ludwig, H. -G.; Porto de Mello, G. F. +4 more
Context. The determination of stellar effective temperature (Teff) in F, G, and K stars using Hα profile fitting is a quite remarkable and powerful tool because it does not depend on reddening and is only slightly sensitive to other atmospheric parameters. Nevertheless, this technique is not frequently used because of the complex proced…
On the Origin of Ortho-Gardenhose Heliospheric Flux
Lockwood, Mike; Owens, Mathew J.; Macneil, Allan
Parker-spiral theory predicts that the heliospheric magnetic field (HMF) will have components of opposite polarity radially toward the Sun and tangentially antiparallel to the solar rotation direction (i.e., in Geocentric Solar Ecliptic (GSE) coordinates, with BX/BY<0 ). This theory explains the average orientation of the …
Flying far and fast: the distribution of distant hypervelocity star candidates from Gaia DR2 data
de la Fuente Marcos, R.; de la Fuente Marcos, C.
Context. Hypervelocity stars move fast enough to leave the gravitational field of their home galaxies and venture into intergalactic space. The most extreme examples known have estimated speeds in excess of 1000 km s-1. These can be easily induced at the centres of galaxies via close encounters between binary stars and supermassive blac…
Uncertainty Quantification in Sunspot Counts
Mathieu, Sophie; von Sachs, Rainer; Ritter, Christian +2 more
Observing and counting sunspots constitutes one of the longest-running scientific experiments, with first observations dating back to Galileo (around 1610). Today the sunspot number (SN) time series acts as a benchmark of solar activity in a large range of physical models. An appropriate statistical modeling, adapted to the time series’ complex na…