The Anticipated Supernova Associated with GRB090618

We use the cannonball model of gamma ray bursts (GRBs) and public data from the first day of observations of GRB 090618 to predict its X-ray and optical lightcurves until very late times, and, in particular, the emergence of a photometric and spectroscopic signature of an SN akin to SN1998bw in its optical afterglow with an anticipated peak brightness of magnitude 23 in the R band around July 10, 2009, if extinction in the host galaxy can be neglected.Comment: 10 pages, 2 Figure

Keefektifan Pengelolaan Laboratorium IPA SMP/MTs di Kabupaten Nagekeo, Propinsi Nusa Tenggara Timur

Penelitian ini bertujuan untuk mengetahui: (1) keefektifan pengelolaan laboratorium IPA SMP/MTs di Kabupaten Nagekeo, dan (2) keefektifan pengelolaan laboratorium yang menghasilkan keefektifan pembelajaran IPA, yang dilihat melalui perencanaan, pengorganisasian, pelaksanaan, pengawasan dan evaluasi pengelolaan laboratorium IPA, dan nilai ujian nasional mata pelajaran IPA tahun 2008. Penelitian ini merupakan penelitian survei terhadap populasi 3 SMP/MTs di Kabupaten Nagekeo. Subjek penelitian terdiri dari: kepala sekolah sebanyak 3 responden, koordinator laboratorium sebanyak 3 responden, guru IPA, laboran sebanyak 5 responden dan peserta didik kelas IX tahun pelajaran 2008/2009 sebanyak 168 responden. Pengumpulan data menggunakan observasi, wawancara, dokumentasi dan angket. Pengujian validitas instrument dilakukan dengan metode korelasi. Analisis data dilakukan dengan menggunakan teknik deskriptif kualitatif. Hasil penelitian menunjukkan bahwa: (1) pengelolaan laboratorium IPA SMP/MTs di Kabupaten Nagekeo adalah cukup efektif, yang didukung oleh perencanaan efektif, pengorganisasian kurang efektif, pelaksanaan cukup efektif, pengawasan dan evaluasi kurang efektif, dan (2) keefektifan pengelolaan laboratorium cenderung menghasilkan pembelajaran IPA yang efektif

Correlated Spectral And Temporal Behaviour Of Late-Time Afterglows Of Gamma Ray Bursts

The cannonball (CB) model of gamma ray bursts (GRBs) predicts that the asymptotic behaviour of the spectral energy density of the X-ray afterglow of GRBs is a power-law in time and in frequency where the difference between the temporal and spectral power-law indexes, $\alpha_X-\beta_X$, is restricted to the values 0, 1/2 and 1. Here we report the distributions of the values $\alpha_X$, $\beta_X$ and their difference for a sample of 315 Swift GRBs. This sample includes all Swift GRBs that were detected before August 1, 2012, whose X-ray afterglow extended well beyond 1 day and the estimated error in $\alpha_X-\beta_X$ was $\leq 0.25$. The values of $\alpha_X$ were extracted from the CB model fits to the entire light curves of their X-ray afterglow while the spectral index was extracted by the Swift team from the time integrated X-ray afterglow of these GRBs. We found that the distribution of the difference $\alpha_X-\beta_X$ for these 315 Swift GRBs has three narrow peaks around 0, 1/2 and 1 whose widths are consistent with being due to the measurement errors, in agreement with the CB model prediction.Comment: 12 figures, added references, used data reported in the Swift/XRT light-curve repositor

On The Evolution Of The Spectral Break In The Afterglow Of Gamma Ray Bursts

The temporal evolution of the spectral break in the time resolved spectral energy density of the broad band afterglow of gamma ray bursts (GRBs) 091127 and 080319B was shown recently to be inconsistent with that expected for the cooling break in the standard fireball model of GRBs. Here we show that it is, however, in good agreement with the predicted temporal evolution of the smooth injection break/bend in the cannonball model of GRBs

GRB 130603B: No Compelling Evidence For Neutron Star Merger

Near infrared (NIR) flare/rebrightening in the afterglow of the short hard gamma ray burst (SHB) 130603B measured with the Hubble Space Telescope (HST) and an alleged late-time X-ray excess were interpreted as possible evidence of a neutron-star merger origin of this SHB. However, the X-ray afterglow that was measured with the Swift-XRT and Newton XMM have the canonical behaviour of a synchrotron afterglow produced by a highly relativistic jet. The H-band flux observed with HST 9.41 days after burst is that expected from the measured late-time X-ray afterglow. A late-time flare/re-brightening of a NIR-Optical afterglow of SHB can be produced by jet collision with an interstellar density bump, or by a kilonova, but jet plus kilonova can be produced also by the collapse of compact stars (neutron star, strange star, or quark star) to a more compact object due to cooling, loss of angular momentum, or mass accretion.Comment: 8 pages, 1 figur