Search Publications

Analysis of a custom support vector machine for photometric redshift estimation and the inclusion of galaxy shape information
DOI: 10.1051/0004-6361/201629558 Bibcode: 2017A&A...600A.113J

Singal, J.; Jones, E.


Aims: We present a custom support vector machine classification package for photometric redshift estimation, including comparisons with other methods. We also explore the efficacy of including galaxy shape information in redshift estimation. Support vector machines, a type of machine learning, utilize optimization theory and supervised learni…

2017 Astronomy and Astrophysics
eHST 35
Epoch of reionization 21 cm forecasting from MCMC-constrained semi-numerical models
DOI: 10.1093/mnras/stx420 Bibcode: 2017MNRAS.468..122H

Davé, Romeel; Finlator, Kristian; Hassan, Sultan +1 more

The recent low value of Planck Collaboration XLVII integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavouring extended reionization scenarios. This will have a significant impact on the 21 cm power spectrum. Using a semi-numerical framework, we improve our model from instantaneous to includ…

2017 Monthly Notices of the Royal Astronomical Society
Planck 35
Analysis and modelling of recurrent solar flares observed with Hinode/EIS on March 9, 2012
DOI: 10.1051/0004-6361/201629703 Bibcode: 2017A&A...601A..39P

Mason, H. E.; Del Zanna, G.; Pariat, E. +4 more

Three homologous C-class flares and one last M-class flare were observed by both the Solar Dynamics Observatory (SDO) and the Hinode EUV Imaging Spectrometer (EIS) in the AR 11429 on March 9, 2012. All the recurrent flares occurred within a short interval of time (less than 4 h), showed very similar plasma morphology and were all confined, until t…

2017 Astronomy and Astrophysics
Hinode 35
HP2 survey. III. The California Molecular Cloud: A sleeping giant revisited
DOI: 10.1051/0004-6361/201731221 Bibcode: 2017A&A...606A.100L

Alves, João; Lada, Charles J.; Lombardi, Marco +1 more

We present new high resolution and dynamic range dust column density and temperature maps of the California Molecular Cloud derived from a combination of Planck and Herschel dust-emission maps, and 2MASS NIR dust-extinction maps. We used these data to determine the ratio of the 2.2 µm extinction coefficient to the 850 µm opacity and fo…

2017 Astronomy and Astrophysics
Herschel Planck 35
Photospheric and coronal magnetic fields in six magnetographs. II. Harmonic scaling of field intensities
DOI: 10.1051/0004-6361/201730863 Bibcode: 2017A&A...604A...7V

Mursula, Kalevi; Virtanen, Ilpo

Context. Photospheric magnetic fields have been observed since the 1970s by several ground-based and satellite instruments. While the different instruments show a fairly similar large-scale structure and temporal evolution of the photospheric magnetic field, the magnetic field intensity varies significantly between the observations.
Aims: We …

2017 Astronomy and Astrophysics
SOHO 35
Thermal structure of the upper atmosphere of Venus simulated by a ground-to-thermosphere GCM
DOI: 10.1016/j.icarus.2016.09.016 Bibcode: 2017Icar..281...55G

López-Valverde, M. A.; Gilli, G.; González-Galindo, F. +5 more

We present here the thermal structure of the upper atmosphere of Venus predicted by a full self-consistent Venus General Circulation Model (VGCM) developed at Laboratoire de Météorologie Dynamique (LMD) and extended up to the thermosphere of the planet. Physical and photochemical processes relevant at those altitudes, plus a non-orographic GW para…

2017 Icarus
VenusExpress 35
Ten billion years of brightest cluster galaxy alignments
DOI: 10.1038/s41550-017-0157 Bibcode: 2017NatAs...1E.157W

West, Michael J.; Phillipps, Steven; Bremer, Malcolm N. +1 more

A galaxy's orientation is one of its most basic observable properties. Astronomers once assumed that galaxies are randomly oriented in space; however, it is now clear that some have preferred orientations with respect to their surroundings. Chief among these are giant elliptical galaxies found in the centres of rich galaxy clusters. Numerous studi…

2017 Nature Astronomy
eHST 35
Searching for candidates of Lyman continuum sources - revisiting the SSA22 field
DOI: 10.1093/mnras/stw2700 Bibcode: 2017MNRAS.465..316M

Inoue, Akio K.; Yamada, Toru; Iwata, Ikuru +3 more

We present the largest to date sample of hydrogen Lyman continuum (LyC) emitting galaxy candidates at any redshift, with 18 Lyman α emitters (LAEs) and seven Lyman break galaxies (LBGs), obtained from the SSA22 field with Subaru/Suprime-Cam. The sample is based on the 159 LAEs and 136 LBGs observed in the field, all with spectroscopically confirme…

2017 Monthly Notices of the Royal Astronomical Society
eHST 35
Understanding EROS2 observations toward the spiral arms within a classical Galactic model framework
DOI: 10.1051/0004-6361/201730488 Bibcode: 2017A&A...604A.124M

Moniez, M.; Rahvar, S.; Ansari, R. +2 more


Aims: EROS (Expérience de Recherche d'Objets Sombres) has searched for microlensing toward four directions in the Galactic plane away from the Galactic center. The interpretation of the catalog optical depth is complicated by the spread of the source distance distribution. We compare the EROS microlensing observations with Galactic models (in…

2017 Astronomy and Astrophysics
Hipparcos 35
Herschel/HIFI spectral line survey of the Orion Bar. Temperature and density differentiation near the PDR surface
DOI: 10.1051/0004-6361/201628916 Bibcode: 2017A&A...599A..22N

Nagy, Z.; Bergin, E. A.; Gerin, M. +7 more

Context. Photon dominated regions (PDRs) are interfaces between the mainly ionized and mainly molecular material around young massive stars. Analysis of the physical and chemical structure of such regions traces the impact of far-ultraviolet radiation of young massive stars on their environment.
Aims: We present results on the physical and ch…

2017 Astronomy and Astrophysics
Herschel 35