Search Publications
The ROSAT Raster survey in the north ecliptic pole field. X-ray catalogue and optical identifications
Moneti, A.; Hasinger, G.; Capak, P. +4 more
The north ecliptic pole (NEP) is an important region for extragalactic surveys. Deep and wide contiguous surveys are being performed by several space observatories, most currently with the eROSITA telescope. Several more are planned for the near future. We analyse all the ROSAT pointed and survey observations in a region of 40 deg2 arou…
Exploring the Sun's upper atmosphere with neural networks: Reversed patterns and the hot wall effect
Asensio Ramos, A.; Socas-Navarro, H.
We have developed an inversion procedure designed for high-resolution solar spectro-polarimeters, such as those of Hinode and the DKIST. The procedure is based on artificial neural networks trained with profiles generated from random atmospheric stratifications for a high generalization capability. When applied to Hinode data, we find a hot fine-s…
Star formation around three co-moving HAeBe stars in the Cepheus Flare
Saha, P.; Maheswar, G.; Kamath, U. S. +1 more
Context. The presence of three more Herbig Ae/Be (HAeBe) candidates in the Cepheus Flare within a 1.5° radius centered on HD 200775 suggests that star formation is prevalent in a wider region of the LDN 1147/1158, LDN 1172/1174, and LDN 1177 clouds. A number of young stellar objects (YSOs) are found to be distributed toward these cloud complexes a…
The angular-momentum flux in the solar wind observed during Solar Orbiter's first orbit
Verscharen, Daniel; Bruno, Roberto; Maksimovic, Milan +20 more
Aims: We present the first measurements of the angular-momentum flux in the solar wind recorded by the Solar Orbiter spacecraft. Our aim is to validate these measurements to support future studies of the Sun's angular-momentum loss.
Methods: We combined 60-min averages of the proton bulk moments and the magnetic field measured by the Sol…
Investigation of the subsurface structure of a sunspot based on the spatial distribution of oscillation centers inferred from umbral flashes
Chae, Jongchul; Cho, Kyuhyoun; Madjarska, Maria S.
The subsurface structure of a solar sunspot is important for the stability of the sunspot and the energy transport therein. Two subsurface structure models have been proposed, the monolithic and cluster models, but no clear observational evidence supporting a particular model has been found to date. To obtain clues about the subsurface structure o…
Chemodynamics of metal-poor wide binaries in the Galactic halo: Association with the Sequoia event
Hansen, Camilla Juul; Peñarrubia, Jorge; Lépine, Sebastien +4 more
Recently, an increasing number of wide binaries has been discovered. Their chemical and dynamical properties are studied through extensive surveys and pointed observations. However, the formation of these wide binaries is far from clear, although several scenarios have been suggested. In order to investigate the chemical compositions of these syst…
The origin of X-ray emission in 3CRR sources: Hints from mid-infrared Spitzer observations
Li, Shuang-Liang; Gu, Minfeng
Aims: Whether X-ray emission in radio-loud (RL) active galactic nuclei (AGNs) originates from disk coronae or jets is still under debate. For example, the positive relationships in radio-quiet AGNs (such as the optical to X-ray spectral index αOX and Eddington ration λO as well as the X-ray photon index Γ and λO
Gamma-ray bursts as probes of high-redshift Lyman-α emitters and radiative transfer models
Salvaterra, R.; Milvang-Jensen, B.; Fynbo, J. P. U. +7 more
Aims: We present the updated census and statistics of Lyman-α emitting long gamma-ray burst host galaxies (LAE-LGRBs). We investigate the properties of a subsample of LAE-LGRBs and test the shell model that is commonly used to fit Lyman-α (Lyα) emission line spectra.
Methods: We considered all LGRB host galaxies with relevant publicly av…
The OTELO survey. Revealing a population of low-luminosity active star-forming galaxies at z ∼ 0.9
Barrufet, Laia; Gallego, Jesús; Sánchez-Portal, Miguel +16 more
Aims: We study a sample of Hβ emission line sources at z ∼ 0.9 to identify the star-forming galaxies sample and characterise them in terms of line luminosity, stellar mass, star formation rate, and morphology. The final aim is to obtain the Hβ luminosity function of the star-forming galaxies at this redshift.
Methods: We used the red tun…
Morphological study of the nested planetary nebula Hubble 12
Zhang, Yong; Sadjadi, SeyedAbdolreza; Hsia, Chih-Hao +3 more
We present a visible-infrared imaging study of young planetary nebula (PN) Hubble 12 (Hb 12; PN G111.8-02.8) obtained with Hubble Space Telescope (HST) archival data and our own Canada-France-Hawaii Telescope (CFHT) measurements. Deep HST and CFHT observations of this nebula reveal three pairs of bipolar structures and an arc-shaped filament near …