-
T. Krühler,
C. Ledoux,
J. P. U. Fynbo,
P. M. Vreeswijk,
S. Schmidl,
D. Malesani,
L. Christensen,
A. De Cia,
J. Hjorth,
P. Jakobsson, [......],
R. Sánchez-Ramírez,
P. Schady,
S. Schulze,
V. Sudilovsky,
N. R. Tanvir,
G. Tagliaferri,
D. J. Watson,
K. Wiersema,
R. A. M. J. Wijers,
D. Xu
[show abstract]
[hide abstract]
ABSTRACT: [Abridged] Molecular hydrogen H_2 is a key requirement for star-formation,
frequently observed along sightlines in the Galaxy and to the Magellanic
Clouds, but notoriously hard to detect directly beyond z ~ 0. In the DLAs
associated with long gamma-ray bursts (GRBs), which are tightly linked to
vigorous star-formation, H_2 has remained largely elusive, and has been
unequivocally detected only towards GRB 080607 and possibly towards GRB 060206.
Here, we present the discovery of H_2-rich gas, including the presence of
vibrationally-excited H_2^* in the optical spectrum of the afterglow of GRB
120815A at z=2.36 obtained with X-shooter at the VLT. The galactic environment
of GRB 120815A is characterized by a strong DLA with log(N(H)/cm^-2) = 21.95
+/- 0.10, prominent H_2 absorption in the Lyman-Werner bands (log(N(H_2)/cm^-2)
= 20.53 +/- 0.04) and thus a molecular gas fraction log f(H_2)=-1.14 +/- 0.10.
The distance d between the absorbing neutral gas and GRB 120815A is constrained
via photo-excitation modeling of fine-structure and meta-stable transitions of
FeII and NiII to d = 0.5 +/- 0.1 kpc. The DLA metallicity ([Zn/H] = -1.15 +/-
0.11), visual extinction (A_V < 0.15 mag) and dust depletion ([Zn/Fe] = 1.01
+/- 0.09) are intermediate between the values of well-studied, H_2-deficient
GRB-DLAs observed at high spectral resolution, and the approximately solar
metallicity, highly-obscured and H_2-rich GRB 080607 sightline. With respect to
N(H), metallicity, as well as dust-extinction and depletion, GRB 120815A is
fairly representative of the average properties of GRB-DLAs. This demonstrates
that molecular hydrogen is present in at least a fraction of the more typical
GRB-DLAs, and H_2 and H_2^* are probably more wide-spread among GRB-selected
systems than the few examples of previous detections would suggest.
04/2013;
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A. J. Levan,
N. R. Tanvir,
R. L. C. Starling,
K. Wiersema,
K. L. Page,
D. A. Perley,
S. Schulze,
G. A. Wynn,
R. Chornock,
J. Hjorth, [......],
J. P. Osborne,
E. Pian,
R. Sanchez-Ramirez,
B. Schmidt,
I. Skillen,
G. Tagliaferri,
C. Thone,
O. Vaduvescu,
R. A. M. J. Wijers,
B. A. Zauderer
[show abstract]
[hide abstract]
ABSTRACT: We present comprehensive multiwavelength observations of three gamma-ray
bursts (GRBs) with durations of several thousand seconds. We demonstrate that
these events are extragalactic transients; in particular we resolve the
long-standing conundrum of the distance of GRB 101225A (the "Christmas-day
burst"), finding it to have a redshift z=0.847, and showing that two apparently
similar events (GRB 111209A and GRB 121027A) lie at z=0.677 and z=1.773
respectively. The systems show extremely unusual X-ray and optical lightcurves,
very different from classical GRBs, with long lasting highly variable X-ray
emission and optical light curves that exhibit little correlation with the
behaviour seen in the X-ray. Their host galaxies are faint, compact, and highly
star forming dwarf galaxies, typical of "blue compact galaxies". We propose
that these bursts are the prototypes of a hitherto largely unrecognized
population of ultra-long GRBs, that while observationally difficult to detect
may be astrophysically relatively common. The long durations may naturally be
explained by the engine driven explosions of stars of much larger radii than
normally considered for GRB progenitors which are thought to have compact
Wolf-Rayet progenitor stars. However, we cannot unambiguously identify
supernova signatures within their light curves or spectra. We also consider the
alternative possibility that they arise from the tidal disruption of stars by
supermassive black holes.
02/2013;
-
[show abstract]
[hide abstract]
ABSTRACT: X-shooter is a second generation ESO-VLT instrument that had its first light
in October 2009. It is a single object medium-resolution spectrograph whose
main feature is the capability of covering simultaneously in a single
observation the range from 3000 to 24000 Angstrom. This unique capability is
very well suited to investigate the complex spectra of the optical counterparts
of X/gamma ray sources which usually display signatures of different components
in emission and absorption. In July 2012 we observed with X-shooter a small
sample of counterparts of bright IGR sources in order to better determine their
physical properties. We present the first results of these observations.
02/2013;
-
K Wiersema,
P ~A Curran,
T Krühler,
A Melandri,
E Rol,
R ~L ~C Starling,
N ~R Tanvir,
A ~J Horst,
S Covino,
J ~P ~U Fynbo, [......],
C Guidorzi,
L Kaper,
S Kobayashi,
C Kouveliotou,
A ~J Levan,
A Rossi,
A Rowlinson,
I ~A Steele,
A Ugarte Postigo,
S ~D Vergani
mnras. 10/2012; 426:2-22.
-
C. C. Thoene,
J. P. U. Fynbo, P. Goldoni,
A. de Ugarte Postigo,
S. Campana,
S. D. Vergani,
S. Covino,
T. Kruehler,
L. Kaper,
N. Tanvir, [......],
S. Klose,
A. J. Levan,
B. Milvang-Jensen,
A. Nicuesa Guelbenzu,
E. Palazzi,
S. Piranomonte,
G. Tagliaferri,
D. Watson,
K. Wiersema,
R. A. M. J. Wijers
[show abstract]
[hide abstract]
ABSTRACT: Abundances of galaxies at redshifts z > 4 are difficult to obtain from damped
Ly {\alpha} (DLA) systems in the sightlines of quasars (QSOs) due to the Ly
{\alpha} forest blanketing and the low number of high-redshift quasars
detected. Gamma-ray bursts (GRBs) with their higher luminosity are well suited
to study galaxies out to the formation of the first stars at z > 10. Its large
wavelength coverage makes the X-shooter spectrograph an excellent tool to study
the interstellar medium (ISM) of high redshift galaxies, in particular if the
redshift is not known beforehand. Here we determine the properties of a GRB
host at z = 4.66723 from a number of resonant low- and high ionization and
fine-structure absorption lines. This is one of the highest redshifts where a
detailed analysis with medium-resolution data has been possible. We detect one
intervening system at z = 2.18. The velocity components of the absorption lines
are fitted with Voigt-profiles and we determine a metallicity of [M/H] = -1.0
\pm 0.1 using S. The absorption lines show a complicated kinematic structure
which could point to a merger in progress. Si II* together with the restframe
UV energy release determined from GROND data gives us the distance of 0.3 to 1
kpc of the absorbing material from the GRB. We measure a low extinction of AV =
0.24 \pm 0.06 mag using X-ray spectral information and the flux calibrated
X-shooter spectrum. GRB-DLAs have a shallower evolution of metallicity with
redshift than QSO absorbers and no evolution in HI column density or ionization
fraction. GRB hosts at high redshift might continue the trend towards lower
metallicities in the LZ-relation with redshift, but the sample is still too
small to draw a definite conclusion. While the detection of GRBs at z > 4 with
current satellites is still difficult, they are very important for our
understanding of the early epochs of star- and galaxy-formation.
06/2012;
-
K. Wiersema,
P. A. Curran,
T. Kruehler,
A. Melandri,
E. Rol,
R. L. C. Starling,
N. R. Tanvir,
A. J. van der Horst,
S. Covino,
J. P. U. Fynbo, [......],
C. Guidorzi,
L. Kaper,
S. Kobayashi,
C. Kouveliotou,
A. J. Levan,
A. Rossi,
A. Rowlinson,
I. A. Steele,
A. de Ugarte Postigo,
S. D. Vergani
[show abstract]
[hide abstract]
ABSTRACT: [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. Polarimetry can be a major independent diagnostic of
afterglow physics, probing the magnetic field properties and internal structure
of the GRB jets. In this paper we present the first high quality multi-night
polarimetric light curve of a Swift GRB afterglow, aimed at providing a well
calibrated dataset of a typical afterglow to serve as a benchmark system for
modelling afterglow polarisation behaviour. In particular, our dataset of the
afterglow of GRB 091018 (at redshift z=0.971) comprises optical linear
polarimetry (R band, 0.13 - 2.3 days after burst); circular polarimetry (R
band) and near-infrared linear polarimetry (Ks band). We add to that high
quality optical and near-infrared broadband light curves and spectral energy
distributions as well as afterglow spectroscopy. The linear polarisation varies
between 0 and 3%, with both long and short time scale variability visible. We
find an achromatic break in the afterglow light curve, which corresponds to
features in the polarimetric curve. We find that the data can be reproduced by
jet break models only if an additional polarised component of unknown nature is
present in the polarimetric curve. We probe the ordered magnetic field
component in the afterglow through our deep circular polarimetry, finding
P_circ < 0.15% (2 sigma), the deepest limit yet for a GRB afterglow, suggesting
ordered fields are weak, if at all present. Our simultaneous R and Ks band
polarimetry shows that dust induced polarisation in the host galaxy is likely
negligible.
03/2012;
-
R Kaur,
L Kaper,
L ~E Ellerbroek,
D ~M Russell,
D Altamirano,
R Wijnands,
Y -J Yang,
P D'Avanzo,
A Ugarte Postigo,
H Flores,
J ~P ~U Fynbo, P Goldoni,
C ~C Thöne,
A Horst,
M Klis,
C Kouveliotou,
K Wiersema,
E Kuulkers
apjl. 02/2012; 746:L23.
-
GRB Coordinates Network. 01/2012; 12991:1.
-
Joel Vernet,
H. Dekker,
S. D'Odorico,
L. Kaper,
P. Kjaergaard,
F. Hammer,
S. Randich,
F. Zerbi,
P. M. Groot,
J. Hjorth, [......],
P. van Dael,
H. van der Vliet,
L. Venema,
M. Vidali,
J. Vinther,
P. Vola,
R. Winters,
D. Wistisen,
G. Wulterkens,
A. Zacchei
[show abstract]
[hide abstract]
ABSTRACT: 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 installed at the Cassegrain focus of UT2 in 2009. The
instrument covers, in a single exposure, the spectral range from 300 to 2500
nm. It is designed to maximize the sensitivity in this spectral range through
dichroic splitting in three arms with optimized optics, coatings, dispersive
elements and detectors. It operates at intermediate spectral resolution
(R~4,000 - 17,000, depending on wavelength and slit width) with fixed echelle
spectral format (prism cross-dispersers) in the three arms. It includes a
1.8"x4" Integral Field Unit as an alternative to the 11" long slits. A
dedicated data reduction package delivers fully calibrated two-dimensional and
extracted spectra over the full wavelength range. We describe the main
characteristics of the instrument and present its performance as measured
during commissioning, science verification and the first months of science
operations.
10/2011;
-
M. Cadolle Bel,
J. Rodriguez,
P. D'Avanzo,
D. M. Russell,
J. Tomsick,
S. Corbel,
F Lewis,
F. Rahoui,
M. Buxton, P. Goldoni,
E. Kuulkers
[show abstract]
[hide abstract]
ABSTRACT: The microquasar GX 339-4 experienced a new outburst in 2010: it was observed
simultaneously at various wavelengths from radio up to soft gamma-rays. We
focused on observations that are quasi-simultaneous with those made with the
INTEGRAL and RXTE satellites: these were collected in 2010 March-April during
our INTEGRAL Target of Opportunity program, and during some of the other
INTEGRAL observing programs with GX 339-4 in the field-of-view. X-ray
transients are extreme systems that often harbour a black hole, and are known
to emit throughout the whole electromagnetic spectrum when in outburst. The
goals of our program are to understand the evolution of the physical processes
close to the black hole and to study the connections between the accretion and
ejection. We analysed radio, NIR, optical, UV, X-ray and soft gamma-ray
observations. We studied the source evolution in detail by producing light
curves, hardness-intensity diagrams and spectra. We fitted the broadband data
with phenomenological, then physical, models to study the emission coming from
the distinct components. Based on the energy spectra, the source evolved from
the canonical hard state to the canonical soft state. The source showed X-ray
spectral variations that were correlated with changes in radio, NIR and optical
emission. The bolometric flux increased from 0.8 to 2.9*10^{-8} erg cm^{-2}
s^{-1} while the relative flux and contribution of the hot medium globally
decreased. Reprocessing in the disc was likely to be strong at the end of our
observations. The source showed a behaviour similar to that of previous
outbursts, with some small deviations in the hard X-rays parameters' evolution.
The radio, NIR and optical emission from jets was detected, and seen to fade as
the source softened. The results are discussed within the context of disc and
jet models.
09/2011;
-
P. Gandhi,
A. W. Blain,
D. M. Russell,
P. Casella,
J. Malzac,
S. Corbel,
P. D'Avanzo,
F. W. Lewis,
S. Markoff,
M. Cadolle Bel, P. Goldoni,
S. Wachter,
D. Khangulyan,
and A. Mainzer
[show abstract]
[hide abstract]
ABSTRACT: Many X-ray binaries remain undetected in the mid-infrared, a regime where emission from their compact jets is likely to dominate. Here, we report the detection of the black hole binary GX 339-4 with the Wide-field Infrared Survey Explorer (WISE) during a very bright, hard accretion state in 2010. Combined with a rich contemporaneous multiwavelength data set, clear spectral curvature is found in the infrared, associated with the peak flux density expected from the compact jet. An optically thin slope of ~ –0.7 and a jet radiative power of >6 × 1035 erg s–1 (d/8 kpc)2 are measured. A ~24 hr WISE light curve shows dramatic variations in mid-infrared spectral slope on timescales at least as short as the satellite orbital period ~95 minutes. There is also significant change during one pair of observations spaced by only 11 s. These variations imply that the spectral break associated with the transition from self-absorbed to optically thin jet synchrotron radiation must be varying across the full wavelength range of ~3-22 μm that WISE is sensitive to, and more. Based on four-band simultaneous mid-infrared detections, the break is constrained to frequencies of 4.6+3.5 – 2.0 × 1013 Hz in at least two epochs of observation, consistent with a magnetic field B 1.5(± 0.8) × 104 G assuming a single-zone synchrotron emission region. The observed variability implies that either B or the size of the acceleration zone above the jet base is being modulated by factors of ~10 on relatively short timescales.
The Astrophysical Journal Letters 09/2011; 740(1):L13. · 5.53 Impact Factor
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S. D. Vergani,
H. Flores,
S. Covino,
D. Fugazza,
J. Gorosabel,
A. J. Levan,
M. Puech,
R. Salvaterra,
J. C. Tello,
A. de Ugarte Postigo, [......],
J. Hjorth,
P. Jakobsson,
L. Kaper,
A. Melandri,
B. Milvang-Jensen,
J. Sollerman,
G. Tagliaferri,
N. R. Tanvir,
K. Wiersema,
R. A. M. J. Wijers
[show abstract]
[hide abstract]
ABSTRACT: We perform a detailed study of the gamma-ray burst GRB091127/SN2009nz host
galaxy at z=0.490 using the VLT/X-shooter spectrograph in slit and
integral-field unit (IFU). From the analysis of the optical and X-ray afterglow
data obtained from ground-based telescopes and Swift-XRT we confirm the
presence of a bump associated with SN2009nz and find evidence of a possible jet
break in the afterglow lightcurve. The X-shooter afterglow spectra reveal
several emission lines from the underlying host, from which we derive its
integrated properties. These are in agreement with those of previously studied
GRB-SN hosts and, more generally, with those of the long GRB host population.
We use the Hubble Space Telescope and ground based images of the host to
determine its stellar mass (M_star). Our results extend to lower M_star values
the M-Z plot derived for the sample of long GRB hosts at 0.3<z<1.0 adding new
information to probe the faint end of the M-Z relation and the shift of the
LGRB host M-Z relation from that found from emission line galaxy surveys.
Thanks to the IFU spectroscopy we can build the 2D velocity, velocity
dispersion and star formation rate (SFR) maps. They show that the host galaxy
has a perturbed rotation kinematics with evidence of a SFR enhancement
consistent with the afterglow position.
07/2011;
-
J. P. U. Fynbo,
C. Ledoux,
P. Noterdaeme,
L. Christensen,
P. Møller,
A. K. Durgapal, P. Goldoni,
L. Kaper,
J.-K. Krogager,
P. Laursen,
J. R. Maund,
B. Milvang-Jensen,
K. Okoshi,
P. K. Rasmussen,
T. J. Thorsen,
S. Toft,
T. Zafar
[show abstract]
[hide abstract]
ABSTRACT: This is the second paper of a series reporting on the results from a survey conducted with the ESO VLT/X-shooter spectrograph. We target high-metallicity damped Lyman α absorbers (DLAs) with the aim of investigating the relation between galaxies detected in emission and those detected in absorption. Here, we report on the discovery of the galaxy counterpart of the zabs= 2.58 DLA on the line-of-sight to the z= 3.07 quasar SDSS J 091826.16+163609.0 (hereafter Q 0918+1636). The galaxy counterpart of the DLA is detected in the [O iii]λ5007 and [O ii]λλ3726, 3729 emission lines redshifted into the NIR at an impact parameter of 2.0 arcsec (16 kpc at z= 2.58). Lyα emission is not detected down to a 3σ detection limit of 5 × 10−18 erg s−1 cm−2, which, compared to the strength of the oxygen lines, implies that Lyα emission from this galaxy is suppressed by more than an order of magnitude. The DLA has one of the highest metallicities measured so far at comparable redshifts. We find evidence for substantial depletion of refractory elements on to dust grains. Fitting the main metal line component of the DLA, which is located at zabs= 2.5832, we measure the metal abundances from Zn ii, S ii, Si ii, Cr ii, Mn ii, Fe ii and Ni ii to be −0.12 ± 0.05, −0.26 ± 0.05, −0.46 ± 0.05, −0.88 ± 0.05, −0.92 ± 0.05, −1.03 ± 0.05 and −0.78 ± 0.05, respectively. In addition, we detect absorption in the Lyman and Werner bands of molecular hydrogen (H2), which represents the first detection of H2 molecules with X-shooter. The background quasar Q 0918+1636 is amongst the reddest QSOs at redshifts 3.02 < z < 3.12 from the SDSS catalogue. Its UV to NIR spectrum is well fitted by a composite QSO spectrum reddened by SMC-/LMC-like extinction curves at zabs= 2.58 with a significant amount of extinction given by AV≈ 0.2 mag. This supports previous claims that there may be more metal-rich DLAs missing from current samples due to dust reddening of the background QSOs. The fact that there is evidence for dust both in the central emitting regions of the galaxy (as evidenced by the lack of Lyα emission) and at an impact parameter of 16 kpc (as probed by the DLA) suggests that dust is widespread in this system.
Monthly Notices of the Royal Astronomical Society 05/2011; 413(4):2481 - 2488. · 4.90 Impact Factor
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M. Sparre,
J. Sollerman,
J. P. U. Fynbo,
D. Malesani, P. Goldoni,
A. de Ugarte Postigo,
S. Covino,
V. D'Elia,
H. Flores,
F. Hammer, [......],
L. Kaper,
G. Leloudas,
A. J. Levan,
B. Milvang-Jensen,
S. Schulze,
G. Tagliaferri,
N. R. Tanvir,
D. J. Watson,
K. Wiersema,
R. A. M. J. Wijers
[show abstract]
[hide abstract]
ABSTRACT: We report on the spectroscopic detection of supernova SN 2010ma associated
with the long gamma-ray burst GRB 101219B. We observed the optical counterpart
of the GRB on three nights with the X-shooter spectrograph at the VLT. From
weak absorption lines, we measure a redshift of z = 0.55. The first epoch
UV--near-infrared afterglow spectrum, taken 11.6 hr after the burst, is well
fit by a power law consistent with the slope of the X-ray spectrum. The second
and third epoch spectra (obtained 16.4 and 36.7 days after the burst), however,
display clear bumps closely resembling those of the broad-lined type-Ic SN
1998bw if placed at z=0.55. Apart from demonstrating that spectroscopic SN
signatures can be observed for GRBs at these large distances, our discovery
makes a step forward in establishing a general connection between GRBs and SNe.
In fact, unlike most previous unambiguous GRB-associated SNe, GRB 101219B has a
large gamma-ray energy (E_iso = 4.2 x 10^{51} erg), a bright afterglow, and
obeys the "Amati" relation, thus being fully consistent with the cosmological
population of GRBs.
The Astrophysical Journal Letters 05/2011; 735(1). · 5.53 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: GRB 100418A was an intermediate duration GRB detected by Swift. It showed an initially dim optical afterglow that had a late increase in brightness, reaching its maximum several hours after the burst onset, unlike typical afterglows that peak tens of seconds after. It also displayed a bright X-ray and radio counterpart. In this paper we present the observations of the afterglow obtained with X-shooter. Three epochs were obtained, 0.4, 1.4, and 2.4 days after the burst. In these spectra, each covering the range from 3000 to 24800 Å, we detect abundant absorption features with 4 velocity components, and emission lines from the host galaxy with 2 additional velocity components. In one single velocity component, we detect a Fe II* 2396 Å fine structure feature which disappears from the first to the second epoch indicating that it is due to the effect of the GRB radiation on its environment. We consider it to be the closest absorption component to the GRB itself, for which we determine a redshift of z = 0.6239 ± 0.0002. From the Hα to [N II] ratio we determine a host galaxy metallicity of 0.5 solar (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Astronomische Nachrichten 03/2011; 332(3):297 - 298. · 1.01 Impact Factor
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H. Flores, P. Goldoni,
F. Royer,
S. Piranomonte,
S.D. Vergani,
F. Onori,
E. Palazzi,
S. Covino,
S. Randich,
F. Hammer,
E. Pian,
S. Savaglio,
G. Tagliaferri
[show abstract]
[hide abstract]
ABSTRACT: Using the integral field unit of X-shooter at VLT, we have recovered the first velocity fields of GRB host galaxies at redshift <0.6. This facility is able to recover not only the velocity fields from almost all emission lines thanks to an unrivaled wavelength coverage, but also to recover maps of physical properties. We present the preliminary analysis of X-shooter/IFU observations dedicated to the study of GRB host galaxies undertaken in the frame of the Italian-French GTO program. Our goal is to understand the physical processes at the origin of the GRB by analyzing in detail the spatial distributions of the kinematics, metallicities, extinction, star-formation, and how they are inter-related (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Astronomische Nachrichten 03/2011; 332(3):288 - 291. · 1.01 Impact Factor
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Astronomische Nachrichten 03/2011; 332:281-282. · 1.01 Impact Factor
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S. Piranomonte,
S. D. Vergani,
F. Onori,
S. Savaglio,
E. Palazzi,
H. Flores,
S. Covino, P. Goldoni,
S. Randich,
F. Hammer,
E. Pian,
G. Tagliaferri
[show abstract]
[hide abstract]
ABSTRACT: Gamma-ray bursts (GRBs) are the most powerful explosions since the formation of the Universe, associated with the death of massive stars or mergers of compact stellar objects. Several recent striking results strongly support the idea that host galaxies of GRBs are opening a new view on our understanding of galaxy formation and evolution, back to the very primordial universe at z ∼ 8. They form a unique sample of galaxies which cover a wide range of redshift, they are typically weak with low mass and unlike other methods they are not selected on luminosity. In recent years, thanks to the support of new generation instruments, multi-band photometry and spectroscopy allow us to better investigate the properties of these host galaxies (e.g., stellar mass, age, SFR, metallicity), to study their possible evolution and to compare them with field galaxies and other classes of galaxies. GRB host spectroscopy is one of the main science drivers behind the X-shooter spectrograph. In this paper, we present the first results of the program devoted to Italian-French GTO multiband spectroscopy of GRB host galaxies with X-shooter (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Astronomische Nachrichten 02/2011; 332(3):283 - 287. · 1.01 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: We report preliminary results of the observation of the GRB 021004 host galaxy and field obtained with the new VLT/X-shooter spectrograph. Thanks to the X-shooter wide spectral range we could detect many emission lines associated to the GRB host at z = 2.33102. Moreover we identify [O III] λλ 4959, 5007 Äemission lines at z = 2.33184 associated with a close-by galaxy possibly interacting with the GRB host. We do not detect any counterpart of the foreground absorbers found in the afterglow spectra of GRB 021004 (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Astronomische Nachrichten 02/2011; 332(3):292 - 294. · 1.01 Impact Factor
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GRB Coordinates Network. 01/2011; 11607:1.
