Publications (159)
The 2175 Ã extinction feature in the optical afterglow spectrum of GRB 180325A at z=2.25
T. Zafar, K. E. Heintz, J. P. U. Fynbo +26
The UV extinction feature at 2175 Ã is ubiquitously observed in the Galaxy but is rarely detected at high redshifts. Here we report the spectroscopic detection of the 2175 Ã bump o…
The host galaxy of the short GRB111117A at : impact on the short GRB redshift distribution and progenitor channels
J. Selsing, T. Krühler, D. Malesani +26
It is notoriously difficult to localize short -ray bursts (sGRBs) and their hosts to measure their redshifts. These measurements, however, are critical to constrain the nature…
Spectroscopy of the short-hard GRB 130603B: The host galaxy and environment of a compact object merger
A. de Ugarte Postigo, C. C. Thoene, A. Rowlinson +40
Short duration gamma-ray bursts (SGRBs) are thought to be related to the violent merger of compact objects, such as neutron stars or black holes, which makes them promising sources…
The VLT-FLAMES Tarantula Survey II: R139 revealed as a massive binary system
W. D. Taylor, C. J. Evans, H. Sana +22
We report the discovery that R139 in 30 Doradus is a massive spectroscopic binary system. Multi-epoch optical spectroscopy of R139 was obtained as part of the VLT-FLAMES Tarantula…
Spectrophotometric analysis of GRB afterglow extinction curves with X-shooter
J. Japelj, S. Covino, A. Gomboc +21
In this work we use gamma-ray burst (GRB) afterglow spectra observed with the VLT/X-shooter spectrograph to measure rest-frame extinction in GRB lines-of-sight by modeling the broa…
An atlas of 2.4 to 4.1 microns ISO/SWS spectra of early-type stars
A. Lenorzer, B. Vandenbussche, P. Morris +5
We present an atlas of spectra of O- and B-type stars, obtained with the Short Wavelength Spectrometer (SWS) during the Post-Helium program of the Infrared Space Observatory (ISO).…
GRB 020813: polarization in the case of a smooth optical decay
J. Gorosabel, E. Rol, S. Covino +35
We present the results of a VLT polarimetric monitoring campaign of the GRB 020813 optical afterglow carried out in three nights, from 0.88 to 4.20 days after the gamma-ray event.…
First firm spectral classification of an early-B pre-main-sequence star: B275 in M17
B. B. Ochsendorf, L. E. Ellerbroek, R. Chini +4
The optical to near-infrared (300 - 2500 nm) spectrum of the candidate massive Young Stellar Object (YSO) B275, embedded in the star forming region M17, has been observed with X-sh…
RCW36: characterizing the outcome of massive star formation
L. E. Ellerbroek, A. Bik, L. Kaper +6
Massive stars play a dominant role in the process of clustered star formation, with their feedback into the molecular cloud through ionizing radiation, stellar winds and outflows.…
Dynamical Masses for the Large Magellanic Cloud Massive Binary System [L72] LH 54-425
S. J. Williams, D. R. Gies, T. J. Henry +8
We present results from an optical spectroscopic investigation of the massive binary system [L72] LH~54-425 in the LH 54 OB association in the Large Magellanic Cloud. We revise the…
ALMA detections of circumstellar disks in the giant Hii region M17. Probing the intermediate- to high-mass pre-main-sequence population
J. Poorta, M. Hogerheijde, A. de Koter +8
Our current understanding is that intermediate- to high-mass stars form in a way similar to low-mass stars, that is, through disk accretion. However, the physical conditions that p…
The X-shooter GRB afterglow legacy sample (XS-GRB)
J. Selsing, D. Malesani, P. Goldoni +53
In this work we present spectra of all -ray burst (GRB) afterglows that have been promptly observed with the X-shooter spectrograph until 31-03-2017. In total, we obtained spec…
Exploring the consequences of pairing algorithms for binary stars
M. B. N. Kouwenhoven, A. G. A. Brown, S. P. Goodwin +2
Knowledge of the binary population in stellar groupings provides important information about the outcome of the star forming process in different environments (see, e.g., Blaauw 19…
GRB 090313: X-shooter's first shot at a GRB
A. de Ugarte Postigo, P. Goldoni, C. C. Thöne +26
Context. X-shooter is the first second-generation instrument to become operative at the ESO Very Large Telescope (VLT). It is a broad-band medium-resolution spectrograph designed w…
Searching for stellar population in the molecular cloud GRSMC 045.49+00.04
N. Azatyan, E. Nikoghosyan, A. Samsonyan +5
Understanding the characteristics of young stellar populations is essential for deriving insights into star formation processes within parent molecular clouds and the influence of…
Host galaxies of SNe Ic-BL with and without long gamma-ray bursts
J. Japelj, S. D. Vergani, R. Salvaterra +5
Broad-line Ic supernovae (SNe Ic-BL) are a very rare class of core-collapse supernovae exhibiting high ejecta velocities and high kinetic energies. They are the only type of SNe th…
Solving the conundrum of intervening strong MgII absorbers towards GRBs and quasars
L. Christensen, S. D. Vergani, S. Schulze +33
Previous studies have shown that the incidence rate of intervening strong MgII absorbers towards GRBs were a factor of 2 - 4 higher than towards quasars. Exploring the similar size…
VLT/X-shooter spectroscopy of the afterglow of the Swift GRB 130606A: Chemical abundances and reionisation at
O. E. Hartoog, D. Malesani, J. P. U. Fynbo +28
The reionisation of the Universe is thought to have ended around z~6, as inferred from spectroscopy of distant bright background sources, such as quasars (QSO) and gamma-ray burst…
The optical/near-IR spectral energy distribution of the GRB 000210 host galaxy
J. Gorosabel, L. Christensen, J. Hjorth +25
We report on UBVRIZJsHKs-band photometry of the dark GRB 000210 host galaxy. Fitting a grid of spectral templates to its Spectral Energy Distribution (SED), we derived a photometri…
SGR J1550-5418 bursts detected with the Fermi Gamma-ray Burst Monitor during its most prolific activity
A. J. van der Horst, C. Kouveliotou, N. M. Gorgone +32
We have performed detailed temporal and time-integrated spectral analysis of 286 bursts from SGR J1550-5418 detected with the Fermi Gamma-ray Burst Monitor (GBM) in January 2009, r…
The metallicity and dust content of a redshift 5 gamma-ray burst host galaxy
M. Sparre, O. E. Hartoog, T. Krühler +26
Observations of the afterglows of long gamma-ray bursts (GRBs) allow the study of star-forming galaxies across most of cosmic history. Here we present observations of GRB 111008A f…
The Primordial Binary Population - I: A near-infrared adaptive optics search for close visual companions to A star members of Scorpius OB2
M. B. N. Kouwenhoven, A. G. A. Brown, H. Zinnecker +2
We present the results of a near-infrared adaptive optics survey with the aim to detect close companions to Hipparcos members in the three subgroups of the nearby OB association Sc…
Models of the circumstellar medium of evolving, massive runaway stars moving through the Galactic plane
D. M. -A. Meyer, J. Mackey, N. Langer +4
At least 5 per cent of the massive stars are moving supersonically through the interstellar medium (ISM) and are expected to produce a stellar wind bow shock. We explore how the ma…
The mass of the neutron star in Vela X-1
O. Barziv, L. Kaper, M. H. van Kerkwijk +2
We measured the radial-velocity curve of HD77581, the B-supergiant companion of the X-ray pulsar Vela X-1, using 183 high-resolution optical spectra obtained in a nine-month campai…
Investigating the spectroscopic, magnetic and circumstellar variability of the O9 subgiant star HD 57682
J. H. Grunhut, G. A. Wade, J. O. Sundqvist +13
The O9IV star HD 57682, discovered to be magnetic within the context of the MiMeS survey in 2009, is one of only eight convincingly detected magnetic O-type stars. Among this selec…
Optical and near-infrared observations of the GRB020405 afterglow
N. Masetti, E. Palazzi, E. Pian +33
(Abridged) We report on observations of the optical and NIR afterglow of GRB020405. Ground-based optical observations started about 1 day after the GRB and spanned a period of ~10…
Signatures of a jet cocoon in early spectra of a supernova associated with a -ray burst
L. Izzo, A. de Ugarte Postigo, K. Maeda +39
Long gamma-ray bursts mark the death of massive stars, as revealed by their association with energetic broad-lined stripped-envelope supernovae. The scarcity of nearby events and t…
X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
Joel Vernet, H. Dekker, S. D'Odorico +87
X-shooter is the first 2nd generation instrument of the ESO Very Large Telescope(VLT). It is a very efficient, single-target, intermediate-resolution spectrograph that was installe…
A brown dwarf desert for intermediate mass stars in Sco OB2?
M. B. N. Kouwenhoven, A. G. A. Brown, L. Kaper
We present JHK observations of 22 intermediate-mass stars in Sco OB2, obtained with VLT/NACO. The survey was performed to determine the status of (sub)stellar candidate companions…
On the nature of WO stars: a quantitative analysis of the WO3 star DR1 in IC 1613
F. Tramper, G. Gräfener, O. E. Hartoog +8
Context. Oxygen sequence Wolf-Rayet (WO) stars are thought to represent the final evolutionary stage of the most massive stars. The characteristic strong O vi emission possibly ori…
The Ultraviolet Spectrum and Physical Properties of the Mass Donor Star in HD 226868 = Cygnus X-1
S. M. Caballero-Nieves, D. R. Gies, C. T. Bolton +8
We present an examination of high resolution, ultraviolet spectroscopy from Hubble Space Telescope of the photospheric spectrum of the O-supergiant in the massive X-ray binary HD 2…
How Special Are Dark Gamma-Ray Bursts: A Diagnostic Tool
E. Rol, R. A. M. J. Wijers, C. Kouveliotou +2
We present here a comprehensive study of the optical/near-infrared (IR) upper limits for gamma-ray bursts that have an X-ray afterglow. We have extrapolated the X-ray afterglows to…
MOONS: a Multi-Object Optical and Near-infrared Spectrograph for the VLT
M. Cirasuolo, J. Afonso, R. Bender +77
MOONS is a new conceptual design for a Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope (VLT), selected by ESO for a Phase A study. The baseline des…
Physical parameters of the high-mass X-ray binary 4U1700-37
J. S. Clark, S. P. Goodwin, P. A. Crowther +4
We present the results of a detailed non-LTE analysis of the UV and optical spectrum of the O6.5Iaf+ star HD153919 - the mass donor in the high-mass X-ray binary 4U1700-37. Given t…
K-band spectroscopy of deeply embedded, young OB stars
A. Bik, L. Kaper, M. M. Hanson +1
We have obtained high resolution (R = 10,000) K-band spectra of candidate young massive stars deeply embedded in high-mass star-forming regions. These objects were selected from a…
Radiation-pressure-driven dust waves inside bursting interstellar bubbles
B. B. Ochsendorf, S. Verdolini, N. L. J. Cox +3
Massive stars drive the evolution of the interstellar medium through their radiative and mechanical energy input. After their birth, they form bubbles of hot gas surrounded by a de…
Spectroscopy of HD 77581 and the mass of Vela X-1
M. H. van Kerkwijk, J. van Paradijs, E. J. Zuiderwijk +3
We present new high-resolution, high signal-to-noise optical spectra of HD 77581, the optical counterpart of the X-ray source Vela X-1, and determine radial velocities from these s…
VLT identification of the optical afterglow of the gamma-ray burst GRB 000131 at z=4.50
M. I. Andersen, J. Hjorth, H. Pedersen +16
We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE det…
The mass of the very massive binary WR21a
F. Tramper, H. Sana, N. E. Fitzsimons +4
We present multi-epoch spectroscopic observations of the massive binary system WR21a, which include the January 2011 periastron passage. Our spectra reveal multiple SB2 lines and f…
Summary of IAU GA SpS 5 II: Stellar and Wind Parameters
F. Martins, M. Bergemann, J. M. Bestenlehner +9
The development of infrared observational facilities has revealed a number of massive stars in obscured environments throughout the Milky Way and beyond. The determination of their…
The properties of ten O-type stars in the low-metallicity galaxies IC 1613, WLM and NGC 3109
F. Tramper, H. Sana, A. de Koter +2
Massive stars likely played an important role in the reionization of the Universe, and the formation of the first black holes. Massive stars in low-metallicity environments in the…
On the dust properties of high redshift molecular clouds and the connection to the 2175 Ã extinction bump
K. E. Heintz, T. Zafar, A. De Cia +9
We present a study of the extinction and depletion-derived dust properties of gamma-ray burst (GRB) absorbers at showing the presence of neutral carbon (\ion{C}{I}). By mod…
VLT/X-shooter spectroscopy of the GRB 090926A afterglow
V. D'Elia, J. P. U. Fynbo, S. Covino +21
The aim of this paper is to study the environment and intervening absorbers of the gamma-ray burst GRB 090926A through analysis of optical spectra of its afterglow. We analyze medi…
The fraction of ionizing radiation from massive stars that escapes to the intergalactic medium
N. R. Tanvir, J. P. U. Fynbo, A. de Ugarte Postigo +38
The part played by stars in the ionization of the intergalactic medium remains an open question. A key issue is the proportion of the stellar ionizing radiation that escapes the ga…
Long- and short-term variability in O-star winds II. Quantitative analysis of DAC behaviour
L. Kaper, H. F. Henrichs, J. S. Nichols +1
A quantitative analysis of time series of ultraviolet spectra from a sample of 10 bright O-type stars (cf. Kaper et al. 1996, Paper I) is presented. The migrating discrete absorpti…
Spectroscopic variability of massive pre-main-sequence stars in M17
A. R. Derkink, M. C. RamÃrez-Tannus, L. Kaper +4
It is a challenge to study the formation process of massive stars: their formation time is short, they are few, often deeply embedded, and at relatively large distances. Our strate…
VLT spectroscopy of GRB 990510 and GRB 990712; probing the faint and bright end of the GRB host galaxy population
P. M. Vreeswijk, A. Fruchter, L. Kaper +15
We present time-resolved optical spectroscopy of the afterglows of the gamma-ray bursts GRB 990510 and GRB 990712. Through the identification of several absorption lines in the fir…
Evidence for diffuse molecular gas and dust in the hearts of gamma-ray burst host galaxies
J. Bolmer, C. Ledoux, P. Wiseman +17
Here we built up a sample of 22 GRBs at redshifts observed with X-shooter to determine the abundances of hydrogen, metals, dust, and molecular species. This allows us to st…
Sequential star formation in IRAS 06084-0611 (GGD 12-15): From intermediate-mass to high-mass stars
K. M. Maaskant, A. Bik, L. B. F. M. Waters +5
Context. The formation and early evolution of high- and intermediate-mass stars towards the main sequence involves the interplay of stars in a clustered and highly complex environm…
On the Mass-Loss Rates of Massive Stars in the Low-Metallicity Galaxies IC 1613, WLM and NGC 3109
F. Tramper, H. Sana, A. de Koter +1
We present a spectroscopic analysis of VLT/X-Shooter observations of six O-type stars in the low-metallicity (Z ~ 1/7 Z\odot) galaxies IC 1613, WLM and NGC 3109. The stellar and wi…
Late-epoch optical and near-infrared observations of the GRB000911 afterglow and its host galaxy
N. Masetti, E. Palazzi, E. Pian +28
We present the results of an optical and near-infrared (NIR) monitoring campaign of the counterpart of Gamma-Ray Burst (GRB) 000911, located at redshift z=1.06, from 5 days to more…
VLT/X-shooter spectroscopy of the GRB 120327A afterglow
V. D'Elia, J. P. U. Fynbo, P. Goldoni +19
We present a study of the environment of the Swift long gamma-ray burst GRB 120327A at z ~2.8 through optical spectroscopy of its afterglow. We analyzed medium-resolution, multi-ep…
Discovery of the nearby long, soft GRB 100316D with an associated supernova
R. L. C. Starling, K. Wiersema, A. J. Levan +43
We report the Swift discovery of nearby long, soft gamma-ray burst GRB 100316D, and the subsequent unveiling of its low redshift host galaxy and associated supernova. We derive the…
Quiescent X-ray variability in the neutron star Be/X-ray transient GRO J1750-27
A. Rouco Escorial, R. Wijnands, L. S. Ootes +5
The Be/X-ray transient GRO J1750-27 exhibited a type-II (giant) outburst in 2015. After the source transited to quiescence, we triggered our multi-year Chandra monitoring programme…
A dearth of short-period massive binaries in the young massive star forming region M17: Evidence for a large orbital separation at birth?
H. Sana, M. Ramirez-Tannus, A. de Koter +3
The formation of massive stars remains poorly understood and little is known about their birth multiplicity properties. Here, we investigate the strikingly low radial-velocity disp…
WRAY 977 (GX301-2): A HYPERGIANT WITH PULSAR COMPANION
L. Kaper, H. J. G. L. M. Lamers, E. Ruymaekers +2
Wray 977, the B supergiant companion of the X-ray pulsar GX301-2, should be classified as B1~Ia+, based on a comparison of its optical spectrum to that of zeta1 Sco, a well-known B…
Massive Stars and their Compact Remnants in High-mass X-ray Binaries
L. Kaper, A. van der Meer
In a high-mass X-ray binary (HMXB) a massive star interacts with a neutron-star or black-hole companion in various ways. The gravitational interaction enables the measurement of fu…
Variable polarization in the optical afterglow of GRB 021004
E. Rol, R. A. M. J. Wijers, J. P. U. Fynbo +19
We present polarimetric observations of the afterglow of gamma-ray burst (GRB) 021004, obtained with the Nordic Optical Telescope (NOT) and the Very Large Telescope (VLT) between 8…
Cold gas in the early Universe. Survey for neutral atomic-carbon in GRB host galaxies at 1 < z < 6 from optical afterglow spectroscopy
K. E. Heintz, C. Ledoux, J. P. U. Fynbo +14
We present a survey for neutral atomic-carbon (CI) along gamma-ray burst (GRB) sightlines, which probes the shielded neutral gas-phase in the interstellar medium (ISM) of GRB host…
The radio afterglow of GRB 030329 at centimeter wavelengths: evidence for a structured jet or non-relativistic expansion
A. J. van der Horst, E. Rol, R. A. M. J. Wijers +3
We present our centimeter wavelength (1.4, 2.3 and 4.8 GHz) light curves of the afterglow of GRB 030329, which were obtained with the Westerbork Synthesis Radio Telescope. Modeling…
On the nature of the WO3 star DR1 in IC 1613
F. Tramper, G. Gräfener, O. E. Hartoog +8
We present the results of a quantitative spectroscopic analysis of the oxygen-sequence Wolf- Rayet star DR1 in the low-metallicity galaxy IC 1613. Our models suggest that the stron…
Diffuse interstellar bands in Upper Scorpius: Probing variations in the DIB spectrum due to changing environmental conditions
D. A. I. Vos, N. L. J. Cox, L. Kaper +2
We study the effects of local environmental conditions affecting the diffuse interstellar band (DIB) carriers within the Upper Scorpius subgroup of the Sco OB2 association. We obta…
New constraints on the physical conditions in H-bearing GRB-host damped Lyman- absorbers
K. E. Heintz, J. Bolmer, C. Ledoux +25
We report the detections of molecular hydrogen (H), vibrationally-excited H (H), and neutral atomic carbon (CI), in two new afterglow spectra of GRBs\,181020A ($z=2.9…
Massive pre-main-sequence stars in M17: and overtone CO bandhead emission and the thermal infrared
J. Poorta, M. C. RamÃrez-Tannus, A. de Koter +4
Recently much progress has been made in probing the embedded stages of massive star formation, pointing to formation scenarios akin to a scaled up version of low-mass star formatio…
Multi-Object Spectroscopy with the European ELT: Scientific synergies between EAGLE & EVE
C. J. Evans, B. Barbuy, P. Bonifacio +29
The EAGLE and EVE Phase A studies for instruments for the European Extremely Large Telescope (E-ELT) originated from related top-level scientific questions, but employed different…
VLT K-band spectroscopy of massive stars deeply embedded in IRAS sources with UCHII colours
A. Bik, L. Kaper, M. M. Hanson +1
We have obtained high resolution (R = 10,000) K-band spectra of candidate young massive stars deeply embedded in (ultra-) compact HII regions (UCHIIs). In these clusters, three typ…
Probing the Early Evolution of Young High-Mass Stars
E. Puga, A. Bik, L. B. M. F. Waters +22
Near-infrared imaging surveys of high-mass star-forming regions reveal an amazingly complex interplay between star formation and the environment (Churchwell et al. 2006; Alvarez et…
The primordial binary population II: Recovering the binary population for intermediate mass stars in Sco OB2
M. B. N. Kouwenhoven, A. G. A. Brown, S. F. Portegies Zwart +1
We characterize the binary population in the young and nearby OB association Scorpius OB2 using available observations of visual, spectroscopic, and astrometric binaries with inter…
On the mass distribution of neutron stars in HMXBs
A. van der Meer, L. Kaper, M. H. van Kerkwijk +1
We present the results of a monitoring campaign of three eclipsing high-mass X-ray binaries (HMXBs: SMC X-1, LMC X-4 and Cen X-3). High-resolution VLT/UVES spectra are used to meas…
X-Shooting ULLYSES: Massive stars at low metallicity VI. Atmosphere and mass-loss properties of O-type giants in the Small Magellanic Cloud
Frank Backs, S. A. Brands, A. de Koter +21
Mass loss through a stellar wind is an important physical process that steers the evolution of massive stars and controls the properties of their end-of-life products, such as the…
Detailed optical and near-infrared polarimetry, spectroscopy and broadband photometry of the afterglow of GRB 091018: Polarisation evolution
K. Wiersema, P. A. Curran, T. Kruehler +30
[Abridged] A number of phenomena have been observed in GRB afterglows that defy explanation by simple versions of the standard fireball model, leading to a variety of new models. P…
The Primordial Binary Population in OB Associations
M. B. N. Kouwenhoven, A. G. A. Brown, A. Gualandris +3
For understanding the process of star formation it is essential to know how many stars are formed as singles or in multiple systems, as a function of environment and binary paramet…
The MiMeS Survey of Magnetism in Massive Stars: Introduction and overview
G. A. Wade, C. Neiner, E. Alecian +47
The MiMeS project is a large-scale, high resolution, sensitive spectropolarimetric investigation of the magnetic properties of O and early B type stars. Initiated in 2008 and compl…
Discovery of the magnetic field in the pulsating B star beta Cephei
H. F. Henrichs, J. A. de Jong, E. Verdugo +17
Although the star itself is not He enriched, the periodicity and the variability in the UV wind lines of the pulsating B1 IV star beta Cep are similar to what is observed in magnet…
A VLT spectroscopic study of the ultracompact HII region G29.96-0.02
N. L. Martin-Hernandez, A. Bik, L. Kaper +2
A high quality, medium-resolution K-band spectrum has been obtained of the ultracompact HII region G29.96-0.02 with the Very Large Telescope (VLT). The slit was positioned along th…
The young stellar content of the giant HII regions M8, G333.6-0.2, and NGC6357 with VLT/KMOS
M. C. RamÃrez-Tannus, J. Poorta, A. Bik +14
Context: The identification and characterisation of populations of young massive stars in (giant) HII regions provides important constraints on i) the formation process of massive…
GRB 100219A with X-shooter - abundances in a galaxy at z = 4.7
C. C. Thoene, J. P. U. Fynbo, P. Goldoni +24
Abundances of galaxies at redshifts z > 4 are difficult to obtain from damped Ly α (DLA) systems in the sightlines of quasars (QSOs) due to the Ly α forest blanketing and the low…
GRB 120422A/SN 2012bz: Bridging the Gap between Low- And High-Luminosity GRBs
S. Schulze, D. Malesani, A. Cucchiara +62
At low redshift, a handful of gamma-ray bursts (GRBs) have been discovered with peak luminosities () substantially lower than the average…
The unpolarized macronova associated with the gravitational wave event GW170817
S. Covino, K. Wiersema, Y. Z. Fan +37
The merger of two dense stellar remnants including at least one neutron star (NS) is predicted to produce gravitational waves (GWs) and short duration gamma ray bursts (GRBs). In t…
Science Case and Requirements for the MOSAIC Concept for a Multi-Object Spectrograph for the European Extremely Large Telescope
C. J. Evans, M. Puech, B. Barbuy +55
Over the past 18 months we have revisited the science requirements for a multi-object spectrograph (MOS) for the European Extremely Large Telescope (E-ELT). These efforts span the…
VLT/UVES spectroscopy of Wray 977, the hypergiant companion to the X-ray pulsar GX301-2
L. Kaper, A. van der Meer, F. Najarro
Model atmosphere fits to high-resolution optical spectra of Wray 977 confirm the B hypergiant classification of the massive companion to the X-ray pulsar GX301-2. The models give a…
Phase-dependent changes in the wind lines in the HMXRB's SMC X-1 and 4U1700-37
R. C. Iping, G. Sonneborn, L. Kaper +1
The High Mass X-ray Binaries (HMXRB's) SMC X-1 and 4U1700-37 have been observed with FUSE to study the effect of the X-ray source on the stellar wind of the primary. In both system…
Galaxy counterparts of metal-rich damped Lyman-alpha absorbers - II. A solar-metallicity and dusty DLA at z_abs=2.58
J. P. U. Fynbo, C. Ledoux, P. Noterdaeme +14
[Abridged]. Here, we report on the discovery of the galaxy counterpart of the z_abs=2.58 DLA on the line-of-sight to the z=3.07 quasar SDSS J091826.16+163609.0. The galaxy counterp…
A relation between the radial velocity dispersion of young clusters and their age: Evidence for hardening as the formation scenario of massive close binaries
M. C. RamÃrez-Tannus, F. Backs, A. de Koter +8
The majority of massive stars ( ) in OB associations are found in close binary systems. Nonetheless, the formation mechanism of these close massive binaries is…
A new population of ultra-long duration gamma-ray bursts
A. J. Levan, N. R. Tanvir, R. L. C. Starling +38
We present comprehensive multiwavelength observations of three gamma-ray bursts (GRBs) with durations of several thousand seconds. We demonstrate that these events are extragalacti…
The luminous, massive and solar metallicity galaxy hosting the Swift gamma-ray burst, GRB 160804A at z = 0.737
K. E. Heintz, D. Malesani, K. Wiersema +19
We here present the spectroscopic follow-up observations with VLT/X-shooter of the Swift long-duration gamma-ray burst GRB 160804A at z = 0.737. Typically, GRBs are found in low-ma…
Highly-ionized metals as probes of the circumburst gas in the natal regions of gamma-ray bursts
K. E. Heintz, D. Watson, P. Jakobsson +18
We present here a survey of high-ionization absorption lines in the afterglow spectra of long-duration gamma-ray bursts (GRBs) obtained with the VLT/X-shooter spectrograph. Our mai…
Massive stars on the verge of exploding: the properties of oxygen sequence Wolf-Rayet stars
F. Tramper, S. M. Straal, D. Sanyal +7
Context. Oxygen sequence Wolf-Rayet (WO) stars represent a very rare stage in the evolution of massive stars. Their spectra show strong emission lines of helium-burning products, i…
The mysterious optical afterglow spectrum of GRB140506A at z=0.889
J. P. U. Fynbo, T. Krühler, K. Leighly +40
Context. Gamma-ray burst (GRBs) afterglows probe sightlines to star-forming regions in distant star-forming galaxies. Here we present a study of the peculiar afterglow spectrum of…
Strategies for prompt searches for GRB afterglows: the discovery of the GRB 001011 optical/near-infrared counterpart using colour-colour selection
J. Gorosabel, J. U. Fynbo, J. Hjorth +25
We report the discovery of the optical and near-infrared counterparts to GRB 001011. The GRB 001011 error box determined by Beppo-SAX was simultaneously imaged in the near-infrared…
On the jet structure and magnetic field configuration of GRB 020813
D. Lazzati, S. Covino, J. Gorosabel +32
The polarization curve of GRB 020813 is discussed and compared to different models for the structure, evolution and magnetisation properties of the jet and the interstellar medium…
The star-formation rate in the host of GRB 990712
P. M. Vreeswijk, R. P. Fender, M. A. Garrett +3
We have observed the host galaxy of GRB 990712 at 1.4 GHz with the Australia Telescope Compact Array, to obtain an estimate of its total star-formation rate. We do not detect a sou…
R144 revealed as a double-lined spectroscopic binary
H. Sana, T. van Boeckel, F. Tramper +7
R144 is a WN6h star in the 30 Doradus region. It is suspected to be a binary because of its high luminosity and its strong X-ray flux, but no periodicity could be established so fa…
The host galaxy of GRB010222: The strongest damped Lyman-alpha system known
I. Salamanca, L. Kaper, P. M. Vreeswijk +6
Analysis of the absorption lines in the afterglow spectrum of the gamma-ray burst GRB010222 indicates that its host galaxy (at a redshift of z=1.476) is the strongest damped Lyman-…
GRB990712: First Indication of Polarization Variability in a Gamma-ray Burst Afterglow
E. Rol, R. A. M. J. Wijers, P. M. Vreeswijk +9
We report the detection of significant polarization in the optical afterglow of GRB990712 on three instances 0.44, 0.70 and 1.45 days after the gamma-ray burst, with (P, theta) bei…
Swift Deep Galactic Plane Survey Classification of Swift J170800402551.8 as a Candidate Intermediate Polar Cataclysmic Variable
B. O'Connor, E. Gogus, J. Hare +24
Here, we present the results of our multi-wavelength campaign aimed at classifying \textit{Swift} J170800402551.8 as part of the \textit{Swift} Deep Galactic Plane Survey (DGPS)…
The host of GRB 030323 at z=3.372: a very high column density DLA system with a low metallicity
P. M. Vreeswijk, S. L. Ellison, C. Ledoux +29
We present photometry and spectroscopy of the afterglow of GRB 030323. VLT spectra of the afterglow show damped Lya (DLA) absorption and low- and high-ionization lines at a redshif…
Stellar Wind Variations During the X-ray High and Low States of Cygnus X-1
D. R. Gies, C. T. Bolton, R. M. Blake +10
We present results from Hubble Space Telescope UV spectroscopy of the massive X-ray binary system, HD226868 = Cyg X-1. The spectra were obtained at both orbital conjunction phases…
On the Hipparcos parallaxes of O stars
S. E. Schroeder, L. Kaper, H. J. G. L. M. Lamers +1
We compare the absolute visual magnitude of the majority of bright O stars in the sky as predicted from their spectral type with the absolute magnitude calculated from their appare…
The radial velocity curve of HD153919 (4U1700-37) revisited
G. Hammerschlag-Hensberge, M. H. van Kerkwijk, L. Kaper
We have re-analysed all available high-resolution ultraviolet IUE spectra of the high-mass X-ray binary HD153919/4U1700-37. The radial velocity semi-amplitude of 20.6 +/- 1.0 km/s…