Two Type Ic supernovae in low-metallicity, dwarf galaxies: diversity of explosions (2009)
Young, D. R., Smartt, S. J., Valenti, S., Pastorello, A., Benetti, S., Benn, C. R., ...
We present BVRI photometry and optical spectroscopy of two Type Ic supernovae SN 2007bg and SN 2007bi discovered in wide-field, non-targeted surveys and associated with sub-luminous blue dwarf...
Hurley, K., Rowlinson, A., Bellm, E., Perley, D., Mitrofanov, I. G., Golovin, D. V., ...
GRB 051103 is considered to be a candidate soft gamma repeater (SGR) extragalactic giant magnetar flare by virtue of its proximity on the sky to M81/M82, as well as its time history, localization,...
The effect of metallicity on Cepheid magnitudes and the distance to M33 (2009)
Scowcroft, V., Bersier, D., Mould, J. R., Wood, P. R.
We present the results from a multi-epoch survey of two regions of M33 using the 3.5m WIYN telescope. The inner field is located close to the centre of the galaxy, with the outer region situated...
Rise and fall of the X-ray flash 080330: an off-axis jet? (2009)
Guidorzi, C., Clemens, C., Kobayashi, S., Granot, J., Melandri, A., D'Avanzo, P., ...
X-ray flashes (XRFs) are a class of gamma-ray bursts (GRBs) with the peak energy of the time-integrated spectrum, Ep, below 30 keV, whereas classical GRBs have Ep of a few hundreds keV. Apart from Ep...
Melandri, A., Guidorzi, C., Kobayashi, S., Bersier, D., Mundell, C. G., Milne, P., ...
We present a comprehensive multiwavelength temporal and spectral analysis of the FRED GRB 070419A. The early-time emission in the $\gamma$-ray and X-ray bands can be explained by a central engine...
The unusual X-ray light-curve of GRB 080307: the onset of the afterglow? (2009)
Page, K. L., Willingale, R., O'Brien, P. T., Tanvir, N. R., Osborne, J. P., Zhang, B., ...
Swift-detected GRB 080307 showed an unusual smooth rise in its X-ray light-curve around 100 seconds after the burst, at the start of which the emission briefly softened. This `hump' has a longer...
Early spectroscopic identification of SN 2008D. (2009)
Malesani, D., Fynbo, J.P.U., Hjorth, J., Leloudas, G., Sollerman, J., Stritzinger, M., ...
Original article can be found at: http://www.iop.org/EJ/journal/apjl Copyright American Astronomical Society DOI: 10.1088/0004-637X/692/2/L84 [Full text of this article is not available in the UHRA]
Rise and fall of the X-ray flash 080330: an off-axis jet? (2009)
Guidorzi, C., Clemens, C., Kobayashi, S., Granot, J., Melandri, A., D'Avanzo, P., ...
Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory (ESO). DOI: 10.1051/0004-6361/200911719
Rise and fall of the X-ray flash 080330: an off-axis jet? (2009)
Guidorzi, C., Clemens, C., Kobayashi, S., Granot, J., Melandri, A., D'Avanzo, P., ...
GRB 070714B - Discovery of the Highest Spectroscopically Confirmed Short Burst Redshift (2008)
Graham, J. F., Fruchter, A. S., Levan, A. J., Melandri, A., Kewley, L. J., Levesque, E. M., ...
We detect the optical afterglow and host galaxy of GRB 070714B. Our observations of the afterglow show an initial plateau in the lightcurve for approximately the first 5 to 25 minutes, then...
Core-collapse supernovae in low-metallicity environments and future all-sky transient surveys (2008)
Young, D. R., Smartt, S. J., Mattila, S., Tanvir, N. R., Bersier, D., Chambers, K. C., ...
Aims: Massive stars in low-metallicity environments may produce exotic explosions such as long-duration gamma-ray bursts and pair-instability supernovae when they die as core-collapse supernovae...
Early spectroscopic identification of SN 2008D (2008)
Malesani, D., Fynbo, J. P. U., Hjorth, J., Leloudas, G., Sollerman, J., Stritzinger, M. D., ...
SN 2008D was discovered while following up an unusually bright X-ray transient in the nearby spiral galaxy NGC 2770. We present early optical spectra (obtained 1.75 days after the X-ray transient)...
Gomboc, A., Kobayashi, S., Guidorzi, C., Melandri, A., Mangano, V., Sbarufatti, B., ...
We present a detailed study of the prompt and afterglow emission from Swift GRB 061126 using BAT, XRT, UVOT data and multi-color optical imaging from ten ground-based telescopes. GRB 061126 was a...
High resolution spectroscopy for Cepheids distance determination. I. Line asymmetry (2008)
Nardetto, N., Mourard, D., Kervella, P., Mathias, Ph., Merand, A., Bersier, D.
The ratio of pulsation to radial velocity (the projection factor) is currently limiting the accuracy of the interferometric Baade-Wesselink method. This work aims at establishing a link between the...
Nardetto, N., Stoekl, A., Bersier, D., Barnes, T. G.
Galactic Cepheids in the vicinity of the Sun have a residual line-of-sight velocity, or gamma-velocity, which shows a systematic blueshift of about 2 km/s compared to an axisymmetric rotation model...
The Early-time Optical Properties of Gamma-Ray Burst Afterglows (2008)
Melandri, A., Mundell, C. G., Kobayashi, S., Guidorzi, C., Gomboc, A., Steele, I. A., ...
We present a multiwavelength analysis of 63 Gamma-Ray Bursts observed with the world's three largest robotic optical telescopes, the Liverpool and Faulkes Telescopes (North and South). Optical...
A large-scale survey for variable stars in M33 (2008)
Bersier, D., Hartman, J. D., Stanek, K. Z., Kaluzny, J., ...
We have started a survey of M 33 in order to find variable stars and Cepheids in particular. We have obtained more than 30 epochs of g'r'i' data with the CFHT and the one-square-degree camera...
GRB 070714B - Discovery of the Highest Spectroscopically Confirmed Short Burst Redshift (2008)
Graham, J. F., Fruchter, A. S., Levan, A. J., Nysewander, M., Tanvir, N. R., Dahlen, T., ...
Gemini Nod & Shuffle spectroscopy on the host of the short GRB 070714B shows a single emission line at 7167 angstroms which, based on a grizJHK photometric redshift, we conclude is the 3727 angstrom...
Core-collapse supernovae in low-metallicity environments and future all-sky transient surveys (2008)
Young, D.R., Smartt, S.J., Mattila, S., Tanvir, N.R., Bersier, D., Chambers, K.C., ...
Aims. Massive stars in low-metallicity environments may produce exotic explosions such as long-duration gamma-ray bursts and pair-instability supernovae when they die as core-collapse supernovae...
The Early-Time Optical Properties of Gamma-Ray Burst Afterglows. (2008)
Melandri, A., Mundell, C.G., Kobayashi, S., Guidorzi, C., Gomboc, A., Steele, I.A., ...
Original article can be found at: http://www.iop.org/EJ/journal/apj Copyright American Astronomical Society DOI: 10.1086/591243 [Full text of this article is not available in the UHRA]
Gomboc, A., Kobayashi, S., Guidorzi, C., Melandri, A., Mangano, V., Sbarufatti, B., ...
We present a detailed study of the prompt and afterglow emission from Swift GRB 061126 using BAT, XRT, UVOT data and multicolor optical imaging from 10 ground-based telescopes. GRB 061126 was a long...
Fundamental parameters of Cepheids. IV. Radii and Luminosities (2007)
A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are:
Fouque, P., Arriagada, P., Storm, J., Barnes, T. G., Nardetto, N., Merand, A., ...
The universality of the Cepheid Period-Luminosity relations has been under discussion since metallicity effects have been assumed to play a role in the value of the intercept and, more recently, of...
Ruiz-Velasco, A. E., Swan, H., Troja, E., Malesani, D., Fynbo, J. P. U., Starling, R. L. C., ...
We report on follow-up observations of the GRB 060927 using the ROTSE-IIIa telescope and a suite of larger aperture ground-based telescopes. An optical afterglow was detected 20 s after the burst,...
A Review of Early-Time Optical Follow-ups with 2-m Robotic Telescopes (2006)
Gomboc, A., Guidorzi, C., Mundell, C. G., Melandri, A., Monfardini, A., Bersier, D., ...
We summarise recent deep, rapid GRB follow-up observations using the RoboNet-1.0 network which comprises three fully-robotic 2-m telescopes, the Liverpool Telescope and the Faulkes Telescopes North...
Postigo, A De Ugarte, Fatkhullin, T. A., Johannesson, G., Gorosabel, J., Sokolov, V. V., Castro-Tirado, A. J., ...
Aims. Understand the shape and implications of the multiband light curve of GRB 050408, an X-ray rich (XRR) burst. Methods. We present a multiband optical light curve, covering the time from the...
The early and late-time spectral and temporal evolution of GRB 050716 (2006)
Rol, E., Osborne, J. P., Page, K. L., McGowan, K. E., Beardmore, A. P., O'Brien, P. T ., ...
We report on a comprehensive set of observations of Gamma Ray Burst 050716, detected by the Swift satellite and subsequently followed-up rapidly in X-ray, optical and near infra-red wavebands. The...
The first Swift X-ray flash: the faint afterglow of XRF 050215B (2006)
Levan, Andrew J., Osborne, Julian P., Tanvir, Nial R., Page, Kim L., Rol, Evert, Zhang, B., ...
The definitive version of this paper, with enhancements, is available from http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v648n2/64894/64894.html
Macri, L. M., Stanek, K. Z., Bersier, D., Greenhill, L., Reid, M.
We present initial results from a time-series BVI survey of two fields in NGC 4258 using the Advanced Camera for Surveys onboard the Hubble Space Telescope. This galaxy was selected because of its...
The First DIRECT Distance Determination to a Detached Eclipsing Binary in M33 (2006)
Bonanos, A. Z., Stanek, K. Z., Kudritzki, R. P., Macri, L. M., Sasselov, D. D., Kaluzny, J., ...
We present the first direct distance determination to a detached eclipsing binary in M33, which was found by the DIRECT Project. Located in the OB 66 association at coordinates (alpha,...
The first Swift X-ray Flash: The faint afterglow of XRF 050215B (2006)
Levan, A. J., Osborne, J. P., Tanvir, N. R., Page, K. L., Rol, E., Zhang, B., ...
We present the discovery of XRF 050215B and its afterglow. The burst was detected by the Swift BAT during the check-out phase and observations with the X-ray telescope began approximately 30 minutes...
Long gamma-ray bursts and core-collapse supernovae have different environments (2006)
Fruchter, A.S., Levan, A.J., Strolger, L., Vreeswijk, P.M., Thorsett, S.E., Bersier, D., ...
When massive stars exhaust their fuel they collapse and often produce the extraordinarily bright explosions known as core-collapse supernovae. On occasion, this stellar collapse also powers an even...
Hartman, J. D., Bersier, D., Stanek, K. Z., Kaluzny, J., ...
We have conducted a variability survey of the local group galaxy M33 using g', r', and i' observations from 27 nights spanning 17 months made with the MegaPrime/MegaCam instrument on the 3.6 m CFHT...
Long gamma-ray bursts and core-collapse supernovae have different environments (2006)
Fruchter, A. S., Levan, A. J., Strolger, L., Vreeswijk, P. M., Thorsett, S. E., Bersier, D., ...
When massive stars exhaust their fuel they collapse and often produce the extraordinarily bright explosions known as core-collapse supernovae. On occasion, this stellar collapse also powers an even...
The faint afterglow and host galaxy of the short-hard GRB 060121 (2006)
Levan, A. J., Tanvir, N. R., Fruchter, A. S., Rol, E., Fynbo, J., Hjorth, J., ...
We present optical and X-ray observations of the afterglow and host galaxy of the short-hard GRB 060121. The faint R-band afterglow is seen to decline as t^(-0.66) while the X-ray falls as t^-1.18,...
A photometric redshift of z = 6.39 0.12 for GRB 050904 (2006)
Haislip, J.B., Nysewander, M.C., Reichart, D., Levan, A., Tanvir, N., Cenko, S.B., ...
Evidence for a Supernova Associated with the X-ray Flash 020903 (2006)
Bersier, D., Fruchter, A. S., Gorosabel, J., Levan, A., Burud, I., ...
We present ground-based and Hubble Space Telescope optical observations of the X-ray flash (XRF) 020903, covering 300 days. The afterglow showed a very rapid rise in the first day, followed by a...
Watson, D., Fynbo, J.P.U., Ledoux, C., Vreeswijk, P., Hjorth, J., Smette, A., ...
The optical afterglow spectrum of GRB 050401 (at z=2.8992+/-0.0004) shows the presence of a damped Lyalpha absorber (DLA), with logNHI=22.6+/-0.3. This is the highest column density ever observed in...
The Faint Afterglow and Host Galaxy of the Short Hard GRB 060121. (2006)
Levan, A., Tanvir, N., Fruchter, A.S., Rol, E., Fynbo, J., Hjorth, J., ...
A photometric redshift of z = 6.39 ¿ 0.12 for GRB 050904 (2006)
Haislip, J.B., Nysewander, M.C., Reichart, D.E., Levan, A.J., Tanvir, N., Cenko, S.B., ...
Gamma-ray bursts (GRBs) and their afterglows are the most brilliant transient events in the Universe. Both the bursts themselves and their afterglows have been predicted to be visible out to...
Levan, A., Fruchter, A., Rhoads, J., Mobasher, B., Tanvir, N., Gorosabel, J., ...
We present near-infrared (NIR) and optical observations of the afterglow of GRB 030115. Discovered in an infrared search at Kitt Peak 5 hr after the burst trigger, this afterglow is the faintest ever...
A log N(HI) = 22.6 DLA in a dark gamma-ray burst: the environment of GRB 050401 (2005)
Watson, D., Fynbo, J. P. U., Ledoux, C., Vreeswijk, P., Hjorth, J., Smette, A., ...
The optical afterglow spectrum of GRB050401 (at z=2.8992+/-0.0004) shows the presence of a DLA, with log(nHI)=22.6+/-0.3. This is the highest column density ever observed in a DLA, and is about five...
Kervella, P., Fouque, P., Storm, J., Gieren, W. P., Bersier, D., Mourard, D., ...
Recent interferometric observations of the brightest and angularly largest classical Cepheid, L Carinae, with ESO\'s VLT Interferometer (VLTI) have resolved with high precision the variation of its...
A possible bright blue SN in the afterglow of GRB 020305 (2005)
Gorosabel, J., Fynbo, J. P. U., Fruchter, A., Levan, A., Hjorth, J., Nugent, P., ...
We report on ground-based and HST(+STIS) imaging of the afterglow and host galaxy of the Gamma-Ray Burst (GRB) of March 5 2002. The GRB occurred in a R=25.17+/-0.14 galaxy, which apparently is part...
Levan, A., Patel, S., Kouveliotou, C., Fruchter, A., Rhoads, J., Rol, E., ...
X-ray flashes (XRFs) are, like gamma-ray bursts (GRBs), thought to signal the collapse of massive stars in distant galaxies. Many models posit that the isotropic equivalent energies of XRFs are lower...
Kervella, P., Bersier, D., Mourard, D., Nardetto, N., Foresto, V. Coude Du
Using our interferometric observations of seven classical Cepheids reported in Kervella et al. (2003, Paper I), complemented by previously existing measurements, we derive new calibrations of the...
Kervella, P., Fouque, P., Storm, J., Gieren, W. P., Bersier, D., Mourard, D., ...
Recent interferometric observations of the brightest and angularly largest classical Cepheid, L Carinae, with ESO's VLT Interferometer (VLTI) have resolved with high precision the variation of its...
Kervella, P., Fouque, P., Storm, J., Gieren, W. P., Bersier, D., Mourard, D., ...
Recent interferometric observations of the brightest and angularly largest classical Cepheid, L Carinae, with ESO\'s VLT Interferometer (VLTI) have resolved with high precision the variation of its...
Kervella, P., Fouque, P., Storm, J., Gieren, W. P., Bersier, D., Mourard, D., ...
Recent interferometric observations of the brightest and angularly largest classical Cepheid, L Carinae, with ESO\'s VLT Interferometer (VLTI) have resolved with high precision the variation of its...
Kervella, P., Nardetto, N., Bersier, D., Mourard, D., Foresto, V. Coude Du
We report the angular diameter measurements of seven classical Cepheids (X Sgr, eta Aql, W Sgr, zeta Gem, beta Dor, Y Oph and L Car) that we have obtained with the VINCI instrument, installed at...
Matheson, T., Garnavich, P. M., Stanek, K. Z., Bersier, D., Holland, S. T., Krisciunas, K., ...
We present extensive optical and infrared photometry of the afterglow of gamma-ray burst (GRB) 030329 and its associated supernova (SN) 2003dh over the first two months after detection (2003 March...
Spectroscopic Discovery of the Supernova 2003dh Associated with GRB 030329 (2003)
Stanek, K. Z., Matheson, T., Garnavich, P. M., Martini, P., Berlind, P., Caldwell, N., ...
We present early observations of the afterglow of the Gamma-Ray Burst (GRB) 030329 and the spectroscopic discovery of its associated supernova SN 2003dh. We obtained spectra of the afterglow of GRB...
Bersier, D., Stanek, K. Z., Winn, J., Grav, T., Holman, M. J., Matheson, T., ...
We report UBVRI observations of the optical afterglow of the gamma-ray burst GRB 021004. We observed significant (10-20%) deviations from a power law decay on several time scales, ranging from a few...
The Spectroscopic Variability of GRB 021004 (2002)
Matheson, T., Garnavich, P. M., Foltz, C., West, S., Williams, G., Falco, E., ...
We present spectra of the optical transient (OT) associated with GRB 021004. The spectra show a blue continuum with superposed absorption features and one emission line. We confirm two intervening...
The Strongly Polarized Afterglow of GRB 020405 (2002)
Bersier, D., McLeod, B., Garnavich, P. M., Holman, M. J., Grav, T., Quinn, J., ...
We report polarization measurements and photometry for the optical afterglow of the gamma-ray burst GRB 020405. We measured a highly significant 9.9% polarization (in V band) 1.3 days after the burst...
Garnavich, P. M., Stanek, K. Z., Wyrzykowski, L., Infante, L., Bendek, E., Bersier, D., ...
We present the discovery and follow-up observations of the afterglow of the GRB 011121 and its associated supernova SN 2001ke. Images were obtained with the OGLE 1.3m telescope in BVRI passbands,...
I present photometric and radial velocity data for Galactic Cepheids, most of them being in the southern hemisphere. There are 1250 Geneva 7-color photometric measurements for 62 Cepheids, the...
Using Cepheids to determine the galactic abundance gradient II. Towards the galactic center (2001)
Andrievsky, S. M., Bersier, D., Kovtyukh, V. V., Luck, R. E., Maciel, W. J., Lepine, J. R. D., ...
Based on spectra obtained at the Anglo-Australian Observatory, we present a discussion of the metallicity of the galactic disc derived using Cepheids at galactocentric distances 4-6 kpc. Our new...
Using Cepheids to determine the galactic abundance gradient I. The solar neighbourhood (2001)
Andrievsky, S. M., Kovtyukh, V. V., Luck, R. E., Lepine, J. R. D., Bersier, D., Maciel, W. J., ...
A number of studies of abundance gradients in the galactic disk have been performed in recent years. The results obtained are rather disparate: from no detectable gradient to a rather significant...
Variable Stars in the Fornax Dwarf Galaxy (2001)
We present a search for variable stars in the Fornax dwarf galaxy covering an area of 1/2 a square degree. We have ~30 epochs of VI data. We found and determined periods for more than 500 RR Lyrae,...
Rapid UBVRI Follow-up of the Highly Collimated Optical Afterglow of GRB010222 (2001)
Stanek, K. Z., Garnavich, P. M., Jha, S., Kilgard, R. E., McDowell, J. C., Bersier, D., ...
(Abridged) We present the earliest optical observations of the optical counterpart to the GRB 010222, obtained with the FLWO 1.2-m telescope in UBVRI passbands, starting 3.64 hours after the burst....
I determine a distance to the Fornax dwarf galaxy using stars in the red clump and at the tip of the red giant branch. They are in very good agreement, with $\mu_0 = 20.66 mag$. Comparing the...
Structural Properties of s-Cepheid Velocity Curves (1998)
Kienzle, F., Moskalik, P., Bersier, D., Pont, F.
The light curves of the first overtone Pop. I Cepheids (s-Cepheids) show a discontinuity in their phi_21 vs. P diagram, near P=3.2 day. This feature, commonly attributed to the 2:1 resonance between...