Search Publications
Passband reconstruction from photometry
Jordi, C.; Fabricius, C.; Carrasco, J. M. +1 more
Context. Based on an initial expectation from laboratory measurements or instrument simulations, photometric passbands are usually subject to refinements. These refinements use photometric observations of astronomical sources with known spectral energy distribution.
Aims: This work investigates the methods for and limitations in determining p…
Revised SED of the triple protostellar system VLA 1623-2417
Hogerheijde, M. R.; Harsono, D.; Murillo, N. M. +2 more
Context. VLA 1623-2417 is a triple protostellar system deeply embedded in Ophiuchus A. Sources A and B have a separation of 1.1″, making their study difficult beyond the submillimeter regime. Lack of circumstellar gas emission suggested that VLA 1623-2417 B has a very cold envelope and is much younger than source A, which is generally considered t…
The vertical metallicity gradients of mono-age stellar populations in the Milky Way with the RAVE and Gaia data
Cropper, Mark; Lin, Jane; Casagrande, Luca +3 more
We investigate the vertical metallicity gradients of five mono-age stellar populations between 0 and 11 Gyr for a sample of 18 435 dwarf stars selected from the cross-matched Tycho-Gaia Astrometric Solution and Radial Velocity Experiment (RAVE) Data Release 5. We find a correlation between the vertical metallicity gradients and age, with no vertic…
Confirmation of a New Metal-poor Globular Cluster in the Galactic Bulge
Smith, Leigh C.; Minniti, Dante; Garofalo, Alessia +14 more
We use deep near-IR photometry of the VISTA Variables in the Vía Láctea (VVV) Survey and deep DECam Plane Survey (DECaPS) optical photometry to confirm the physical reality of the candidate globular cluster (GC) Minni 22, which is located in the Galactic bulge. This object, which was detected as a high density region in our maps of bulge red giant…
Discovery of X-ray pulsations in the Be/X-ray binary IGR J06074+2205
Zezas, A.; Reig, P.
Context. IGR J06074+2205 is a poorly studied X-ray source with a Be star companion. It has been proposed to belong to the group of Be/X-ray binaries (BeXBs). In BeXBs, accretion onto the neutron star occurs via the transfer of material from the Be star's circumstellar disk. Thus, in the absence of the disk, no X-ray should be detected.
Aims: …
Intriguing X-ray and optical variations of the γ Cassiopeiae analog HD 45314
Schmitt, J. H. M. M.; Miroshnichenko, A. S.; Zharikov, S. V. +11 more
Context. A growing number of Be and Oe stars, named the γ Cas stars, are known for their unusually hard and intense X-ray emission. This emission could either trace accretion by a compact companion or magnetic interaction between the star and its decretion disk.
Aims: To test these scenarios, we carried out a detailed optical monitoring of HD…
Direction-finding Analysis of the 2012 July 6 Type II Solar Radio Burst at Low Frequencies
Gopalswamy, Nat; Akiyama, Sachiko; Mäkelä, Pertti
The 2012 July 6 X1.1 flare at S13W59 and a halo coronal mass ejection (CME) with a space speed of ∼1900 km s-1 were associated with type III and type II radio bursts. The metric-to-decametric type II radio burst extended down to ∼5 MHz. Simultaneously, a slowly drifting feature with a harmonic structure was observed by Wind and Solar Te…
The Lyα Reference Sample. VIII. Characterizing Lyα Scattering in Nearby Galaxies
Cannon, John M.; Hayes, Matthew; Östlin, Göran +13 more
We examine the dust geometry and Lyα scattering in the galaxies of the Lyman Alpha Reference Sample (LARS), a set of 14 nearby (0.02< z< 0.2) Lyα-emitting and starbursting systems with Hubble Space Telescope Lyα, Hα, and Hβ imaging. We find that the global dust properties determined by line ratios are consistent with other studies, with some…
Update on the X-Ray Variability Plane for Active Galactic Nuclei: The Role of the Obscuration
González-Martín, Omaira
Scaling relations are the most powerful astrophysical tools to set constraints on the physical mechanisms of astronomical sources and to infer properties that cannot be accessed directly. We reinvestigate here one of these scaling relations in active galactic nuclei (AGNs); the so-called X-ray variability plane (or mass-luminosity timescale relati…
Late-time Observations of ASASSN-14lp Strengthen the Case for a Correlation between the Peak Luminosity of Type Ia Supernovae and the Shape of Their Late-time Light Curves
Zurek, David R.; Rest, Armin; Cara, Mihai +5 more
Late-time observations of Type Ia supernovae (SNe Ia), >900 days after explosion, have shown that this type of SN does not suffer an “IR catastrophe” at 500 days as previously predicted. Instead, several groups have observed a slow-down in the optical light curves of these SNe. A few reasons have been suggested for this slow-down, from a changi…