Search Publications
New light on the multiple jets of CRL 618
Velázquez, P. F.; Raga, A. C.; Riera, A. +2 more
Context. Proto-planetary nebulae (pPNe) are thought to represent the transitory phase of the late stages of low- to intermediate-mass stars. Most pPNe show a bipolar or multipolar geometry. The process(es) that transforms the spherical asymptotic giant branch (AGB) ejecta into a bipolar/multipolar geometry is not known in detail. Interactions betw…
Expected number of supergiant fast X-ray transients in the Milky Way
Santangelo, A.; Ducci, L.; Romano, P. +2 more
In the past fifteen years a new generation of X-ray satellites led to the discovery of a subclass of high-mass X-ray binaries (HMXBs) with supergiant companions and a peculiar transient behaviour: supergiant fast X-ray transients (SFXTs). We calculate the expected number of Galactic SFXTs for the first time, using two different statistical approac…
Upper limits to interstellar NH+ and para-NH2- abundances. Herschel-HIFI observations towards Sgr B2 (M) and G10.6-0.4 (W31C)
Menten, K. M.; Persson, C. M.; Lis, D. C. +12 more
The understanding of interstellar nitrogen chemistry has improved significantly with recent results from the Herschel Space Observatory. To set even better constraints, we report here on deep searches for the NH+ ground state rotational transition J = 1.5-0.5 of the 2Π1/2 lower spin ladder, with fine-structure tran…
The host galaxy and Fermi-LAT counterpart of HESS J1943+213
van der Wel, A.; Peter, D.; Domainko, W. +2 more
Context. The very-high energy (VHE, E> 100 GeV) gamma-ray sky shows diverse Galactic and extragalactic source populations. For some sources the astrophysical object class could not be identified so far.
Aims: The nature (Galactic or extragalactic) of the VHE gamma-ray source HESS J1943+213 is explored. We specifically investigate the propo…
Synapses of active galactic nuclei:. Comparing X-ray and optical classifications using artificial neural networks
Papadakis, I. E.; Acosta-Pulido, J. A.; González-Martín, O. +5 more
Context. Many classes of active galactic nuclei (AGN) have been defined entirely through optical wavelengths, while the X-ray spectra have been very useful to investigate their inner regions. However, optical and X-ray results show many discrepancies that have not been fully understood yet.
Aims: The main purpose of the present paper is to st…
Water emission from the high-mass star-forming region IRAS 17233-3606
Codella, C.; Csengeri, T.; Beuther, H. +7 more
We investigate the physical and chemical processes at work during the formation of a massive protostar based on the observation of water in an outflow from a very young object previously detected in H2 and SiO in the IRAS 17233-3606 region. We estimated the abundance of water to understand its chemistry, and to constrain the mass of the…
Molecular absorption in transition region spectral lines
Peter, H.; Curdt, W.; Innes, D. +3 more
Aims: We present observations from the Interface Region Imaging Spectrograph (IRIS) of absorption features from a multitude of cool atomic and molecular lines within the profiles of Si IV transition region lines. Many of these spectral lines have not previously been detected in solar spectra.
Methods: We examined spectra taken from deep …
A multi-method approach to radial-velocity measurement for single-object spectra
Gosset, E.; Damerdji, Y.; Katz, D. +5 more
Context. The derivation of radial velocities from large numbers of spectra that typically result from survey work, requires automation. However, except for the classical cases of slowly rotating late-type spectra, existing methods of measuring Doppler shifts require fine-tuning to avoid a loss of accuracy due to the idiosyncrasies of individual sp…
Reciprocatory magnetic reconnection in a coronal bright point
Ding, M. D.; Chen, P. F.; Ji, H. S. +1 more
Context. Coronal bright points (CBPs) are small-scale and long-duration brightenings in the lower solar corona. They are often explained in terms of magnetic reconnection.
Aims: We aim to study the substructures of a CBP and clarify the relationship among the brightenings of different patches inside the CBP.
Methods: The event was observ…
The virtual observatory service TheoSSA: Establishing a database of synthetic stellar flux standards . II. NLTE spectral analysis of the OB-type subdwarf Feige 110
Rauch, T.; Werner, K.; Kruk, J. W. +3 more
Context. In the framework of the Virtual Observatory (VO), the German Astrophysical VO (GAVO) developed the registered service TheoSSA (Theoretical Stellar Spectra Access). It provides easy access to stellar spectral energy distributions (SEDs) and is intended to ingest SEDs calculated by any model-atmosphere code, generally for all effective temp…