A5020839110- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- SAS software applications and methods
- Astrophysics and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
- Planetary Science and Exploration
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Space Exploration and Technology
- Spectroscopy and Laser Applications
- Isotope Analysis in Ecology
- Pulsars and Gravitational Waves Research
- Particle accelerators and beam dynamics
- Adaptive optics and wavefront sensing
- Solar and Space Plasma Dynamics
- Dark Matter and Cosmic Phenomena
- Gyrotron and Vacuum Electronics Research
- Particle Detector Development and Performance
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
Instituto de Astrofísica de Andalucía
2015-2024
University of Göttingen
2021
Consejo Superior de Investigaciones Científicas
2006-2019
Space Telescope Science Institute
2006
We present the second installment of GOSSS, a massive spectroscopic survey Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R ∼ 2500 digital observations from both hemispheres selected O-Star Catalog (GOSC). In this paper we include bright stars and other objects drawn mostly first version GOSC, all them south δ = −20°, for total number 258 stars. also revise northern sample Paper I to provide full list spectroscopically classified complete B 8, bringing published...
We present the first installment of a massive spectroscopic survey Galactic O stars, based on new, high signal-to-noise ratio, R~2500 digital observations from both hemispheres selected O-Star Catalog Ma\'iz Apell\'aniz et al. (2004) and Sota (2008). The spectral classification system is rediscussed new atlas presented, which supersedes previous versions. Extensive sequences exceptional objects are given, including types Ofc, ON/OC, Onfp, Of?p, Oe, double-lined binaries. remaining normal...
Abstract Most of the light from blazars, active galactic nuclei with jets magnetized plasma that point nearly along line sight, is produced by high-energy particles, up to around 1 TeV. Although are known be ultimately powered a supermassive black hole, how particles accelerated such high energies has been an unanswered question. The process must related magnetic field, which can probed observations polarization jets. Measurements radio optical polarization—the only range available until...
Abstract The lower-energy peak of the spectral energy distribution blazars has commonly been ascribed to synchrotron radiation from relativistic particles in jets. Despite consensus regarding jet emission processes, particle acceleration mechanism is still debated. Here, we present first X-ray polarization observations PG 1553+113, a high-synchrotron-peak blazar observed by Imaging Polarimetry Explorer (IXPE). We detect an degree (10 ± 2)% along electric-vector position angle ψ X = 86° 8°....
Abstract We report the first >99% confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/ γ -ray outburst, 287 ks observation (2022 November 27–30) was taken using Imaging Polarimetry Explorer (IXPE), together with contemporaneous multiwavelength observations from Neil Gehrels Swift observatory and XMM-Newton soft X-rays (0.3–10 keV), NuSTAR hard (3–70 optical Calar Alto Perkins Telescope observatories. Our data suggest that IXPE energy band is at crossover...
Abstract Observations of linear polarization in the 2–8 keV energy range with Imaging X-ray Polarimetry Explorer (IXPE) explore magnetic field geometry and dynamics regions generating nonthermal radiation relativistic jets blazars. These jets, particularly blazars whose spectral distribution peaks at energies, emit X-rays via synchrotron from high-energy particles within jet. IXPE observations X-ray-selected BL Lac–type blazar 1ES 1959+650 on 2022 May 3–4 showed a significant degree Π x =...
On the basis of an extensive new spectroscopic survey Galactic O stars, we introduce Ofc category, which consists normal spectra with C iii λλ4647–4650–4652 emission lines comparable intensity to those Of defining N λλ4634–4640–4642. The former feature is strongly peaked spectral type O5, at all luminosity classes, but preferentially in some associations or clusters and not others. relationships this phenomenon selective λ5696 throughout domain, peculiar, variable Of?p for strong a...
This is the third installment of GOSSS, a massive spectroscopic survey Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R~2500 digital observations selected from O-Star Catalog (GOSC). In this paper we present 142 additional stellar systems with stars both hemispheres, bringing total O-type published within project to 590. Among objects there are 20 stars. We also identify 11 double-lined binaries (SB2s), which 6 O+O type and 5 O+B type, an tripled-lined binary (SB3)...
Abstract We present polarization measurements in the 2–8 keV band from blazar 1ES 0229+200, first extreme high synchrotron peaked source to be observed by Imaging X-ray Polarimetry Explorer (IXPE). Combining two exposures separated about weeks, we find degree of Π X = 17.9% ± 2.8% at an electric-vector position angle ψ 25.°0 4.°6 using a spectro-polarimetric fit joint IXPE and XMM-Newton observations. There is no evidence for or varying significantly with energy time on both short timescales...
Aims. We aim to probe the magnetic field geometry and particle acceleration mechanism in relativistic jets of supermassive black holes. Methods. conducted a polarimetry campaign from radio X-ray wavelengths high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging Polarimetry Explorer (IXPE) measurements 2022 December 6–8. During IXPE observation, we also monitored 421 using Swift -XRT obtained single observation with XMM-Newton improve spectral analysis. The time-averaged polarization...
Aims. Knowledge of rotation periods ( P rot ) is important for understanding the magnetic activity and angular momentum evolution late-type stars, as well evaluating radial velocity signals potential exoplanets identifying false positives. We measured photometric spectroscopic a large sample nearby bright M dwarfs with spectral types from M0 to M9, part our continual effort fully characterize Guaranteed Time Observation programme stars CARMENES survey. Methods. analyse light curves chiefly...
We report the X-ray polarization properties of high-synchrotron-peaked (HSP) blazar PKS 2155−304 based on observations with Imaging Polarimetry Explorer (IXPE). observed source between Oct 27 and Nov 7, 2023. also conducted an extensive contemporaneous multiwavelength (MW) campaign. find that during first half ( T 1 ) IXPE pointing, exhibited highest degree detected for HSP thus far, (30.7 ± 2.0)%; this dropped to (15.3 2.1)% second 2 ). The angle remained stable pointing at 129.4° ±1.8°...
The X-ray polarization observations, made possible with the Imaging Polarimetry Explorer (IXPE), offer new ways of probing high-energy emission processes in astrophysical jets from blazars. Here, we report first observation blazar S4 0954+65 a high optical and state. During our multi-wavelength (MWL) campaign source, detected an flare whose peak coincided flare. This optical-X-ray most likely took place feature moving along parsec-scale jet, imaged at 43 GHz by Very Long Baseline Array...
This paper presents a first observational investigation of the faint Of?p star NGC 1624-2, yielding important new constraints on its spectral and physical characteristics, rotation, magnetic field strength, X-ray emission magnetospheric properties. Modelling spectrum energy distribution, we conclude that 1624-2 is main-sequence mass M ≃ 30 M⊙, infer an effective temperature 35 ± 2 kK log g = 4.0 0.2. Based extensive time series optical observations report significant variability large number...
We provide a complete characterization of the astrophysical properties σ Ori Aa, Ab, B hierarchical triple system and an improved set orbital parameters for highly eccentric Ab spectroscopic binary. compiled data comprising 90 high-resolution spectra covering total time span 1963 days. applied Lehman–Filhés method detailed analysis radial velocity curves performed combined quantitative by means stellar atmosphere code fastwind. used our own plus other available information on photometry...
Aims. Most hot Jupiters are expected to spiral in toward their host stars because the angular momentum of orbital motion is transferred stellar spin. Their orbits can also precess as a result planet-star interactions. Calculations show that both effects might be detected for very-hot exoplanet WASP-12 b using method precise transit-timing over time span about 10 yr.
Context. The first Gaia Data Release (DR1) significantly improved the previously available proper motions for majority of Tycho -2 stars. Aims. We wish to detect runaway stars using DR1 and compare our results with previous searches. Methods. Runaway O BA supergiants were detected a 2D motion method. sample was selected Simbad, spectra from GOSSS project, literature spectral types, photometry processed code CHORIZOS. Results. 76 stars, 17 (possibly 19) them no prior identification as such,...
[ABRIDGED] AIMS. MONOS is collecting information and studying O-type spectroscopic binaries with delta > -20 deg. In this 1st paper we describe the sample provide spectral classifications additional for objects previous SB or EB orbits. future will test validity of solutions calculate new METHODS.The spectra in have 2 sources: GOSSS, which obtaining blue-violet R~2500 spectroscopy thousands massive stars, LiLiMaRlin, a library libraries high-resolution stars obtained from 4 different...
Abstract Blazars are a class of jet-dominated active galactic nuclei with typical double-humped spectral energy distribution. It is common consensus that the synchrotron emission responsible for low frequency peak, while origin high hump still debated. The analysis X-rays and their polarization can provide valuable tool to understand physical mechanisms high-energy blazars. We report first observations BL Lacertae (BL Lac) performed Imaging X-ray Polarimetry Explorer, from which an upper...
We present the results of a three-continent multisite photometric campaign carried out on Algol-type eclipsing binary system Y Cam, in which primary component is multiperiodic δ Sct-type pulsator. The observations consist 86 nights and more than 450 h useful data collected mainly during Northern winter 2002–2003. This means that this most extensive time series for such kind systems obtained so far. These were mostly Johnson V filter, but they also include, first time, nearly complete light...
We use a sample of 19 Gamma Ray Bursts (GRBs) that exhibit single-peaked optical light curves to test the standard fireball model by investigating relationship between time onset afterglow and temporal rising index. Our includes GRBs X-ray flashes for which we derive wide range initial Lorentz factors ($40 < \Gamma 450$). Using plausible parameters typical frequency forward shock is expected lie close band; within this low framework, data constrain $\epsilon_e$ show values derived from early...
We present a refinement of the optical morphologies for galaxies in Catalog Isolated Galaxies that forms basis AMIGA (Analysis interstellar Medium GAlaxies) project. Uniform reclassification using digitized POSS II data benefited from high resolution and dynamic range sky survey. Comparison with independent classifications made an SDSS overlap sample more than 200 confirms reliability early vs. late-type discrimination accuracy spiral subtypes within 1–2. CCD images taken at Observatorio de...