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We report on early observations of the optical afterglow of GRB 070411 obtained by the Cˇrni Vrh 0.6-m, the ROTSE IIIc 0.45-m, and the Tautenburg 1.34-m Schmidt telescope starting within 1 to 5 minutes after the trigger. The derived light curve presents a rising phase, then a plateau followed by a steep decay and finally a jet break. [ABSTRACT FROM AUTHOR]

The majority of bright gamma-ray transients that we observe in the sky, are produced by extragalactic gamma-ray bursts (GRBs). However, we know that there are other kinds of sources that can produce intense bursts of high-energy photons within our own Galaxy. GRB 070610/Swift J195509+261406, being just 1 degree away from the Galactic plane, is one of these sources and presents a peculiar behavior, as it shows strong flaring activity that has been observed in the optical and near infrared. We have gathered multi-wavelength observations of GRB 070610 including optical, near infrared, millimeter and radio observations. Our dataset covers the time from 1 minute after the burst onset to more than 4 months later. Following the burst in the gamma-ray band, the source displayed more than 40 flaring episodes in the optical bands (reaching up to Ic∼15) over a time span of three days, plus a faint infrared flare that was observed at late times. After this time, the source slowly faded away until it became undetectable. [ABSTRACT FROM AUTHOR]

We present multiwavelength observations of the latest two GRB detected by Hete-2 in 2005. For GRB 051022, no optical/nIR afterglow has been detected, in spite of the strong gamma-ray emission and the reported X-ray afterglow discovered by Swift. A mm afterglow was discovered at PdB confirming the association of this event with a luminous (MV = - 21.5) galaxy within the X-ray error box. Spectroscopy of this galaxy shows strong a strong [O II] emission line at z = 0.807, besides weaker [O III] emission. The X-ray spectrum showed evidence of considerable absorption by neutral gas with NH,X-ray = 4.5 × 1022 cm2 (at rest frame). ISM absorption by dust in the host galaxy at z = 0.807 cannot certainly account for the non-detection of the optical afterglow, unless the dust-to-gas ratio is quite different than that seen in our Galaxy. It is possible then that GRB 051022 was produced in an obscured, stellar forming region in its parent host galaxy. For GRB 051028, the data can be interpreted by collimated emission (a jet model with p = 2.4) moving in an homogeneous ISM and with a cooling frequency vc still above the X-rays at 0.5 days after the burst onset. GRB 051028 can be classified as a “gray” or “potentially dark” GRB. The Swift/XRT data are consistent with the interpretation that the reason for the optical dimness is not extra absorption in the host galaxy, but rather the GRB taking place at high-redshift. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The prompt information given by the GRB Coordinates Network (GCN) differs very much for different GRBs. We compare the optical magnitudes quoted in GCNs for some recent events. Our compilation might help in planning coordinated observations in the future. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We report on our program for multiband photometry observations of Optical Transients of Gamma-Ray Bursts at the 152 cm telescope in Loiano. 40 Km south of Bologna, Italy. Observations in the four semesters starting on July 1st, 2001, were performed for 13 events and allowed positive detections for six of them. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The AGILE gamma-ray burst GRB 080514B was the first detected to have emission at energies above 30 MeV and an optical/NIR afterglow. Here we summarize the main results of our observing campaign based on optical/NIR follow-up observations of this event at several observatories, including the multi-channel imager GROND on La Silla and Swift UVOT. The data allowed us to determine a photometric redshift of for this event of z = 1.8-0.3+0.4. [ABSTRACT FROM AUTHOR]