GROND coverage of the main peak of Gamma-Ray Burst 130925A

Abstract

Prompt or early optical emission in gamma-ray bursts is notoriously difficult to measure, and observations of the dozen cases show a large variety of properties. Yet, such early emission promises to help us achieve a better understanding of the GRB emission process(es). We performed dedicated observations of the ultra-long duration (T90 about 7000 s) GRB 130925A in the optical/near-infrared with the 7-channel "Gamma-Ray Burst Optical and Near-infrared Detector" (GROND) at the 2.2m MPG/ESO telescope. We detect an optical/NIR flare with an amplitude of nearly 2 mag which is delayed with respect to the keV--MeV prompt emission by about 300--400 s. The decay time of this flare is shorter than the duration of the flare (500 s) or its delay. While we cannot offer a straightforward explanation, we discuss the implications of the flare properties and suggest ways toward understanding it.

arXiv comment9 pages, 9 figures, accepted for publ. in A&A

References in corpus (56)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs
• The Fermi Gamma-Ray Burst Monitor
• Optical and Long Wavelength Afterglow from Gamma-Ray Bursts
• Observation of contemporaneous optical radiation from a gamma-ray burst
• Discovery of the Onset of Rapid Accretion by a Dormant Massive Black Hole
• Connection Between Energy-dependent Lags And Peak Luminosity In Gamma-ray Bursts
• Lower Limits on Lorentz Factors in Gamma Ray Bursts
• GROND - a 7-channel imager
• An extremely luminous panchromatic outburst from the nucleus of a distant galaxy
• GRB990123, The Optical Flash and The Fireball Model
• Light Curves of GRB Optical Flashes
• GRB 990123: Reverse and Internal Shock Flashes and Late Afterglow
• Constraining GRB Initial Lorentz Factor with the Afterglow Onset Feature and Discovery of a Tight Gamma_0-E_iso Correlation
• The 2175 A dust feature in a Gamma Ray Burst afterglow at redshift 2.45
• The nature of "dark" gamma-ray bursts
• GRB 080913 at redshift 6.7
• A Link between Prompt Optical and Prompt Gamma-Ray Emission in Gamma-Ray Bursts
• The afterglow of GRB 021004: surfing on density waves
• Quasi-blackbody component and radiative efficiency of the prompt emission of gamma-ray bursts
• Gamma Ray Bursts in the comoving frame
• A statistical study of gamma-ray burst afterglows measured by the Swift Ultra-violet Optical Telescope
• The detailed optical light curve of GRB 030329
• GRB 130427A: a Nearby Ordinary Monster
• Energy input and response from prompt and early optical afterglow emission in gamma-ray bursts
• A Theory of Mulicolor Black Body Emission from Relativistically Expanding Plasmas
• Early Optical Afterglows from Wind-Type Gamma-Ray Bursts
• How Long does a Burst Burst?
• Observational evidence of dissipative photospheres in gamma-ray bursts
• The Bright Optical flash and Afterglow from the Gamma-Ray Burst GRB 130427A
• A contemporaneous infrared flash from a long gamma-ray burst: an echo from the central engine
• Regulation of the spectral peak in gamma-ray bursts
• The peak energy of dissipative GRB photospheres
• The ultra-long GRB 111209A - II. Prompt to afterglow and afterglow properties
• A strong optical flare before the rising afterglow of GRB 080129
• On thermalization in gamma-ray burst jets and the peak energies of photospheric spectra
• A hot cocoon in the ultralong GRB 130925A: hints of a PopIII-like progenitor in a low density wind environment
• On the origin of GeV emission in gamma-ray bursts
• Photometric redshifts for GRB afterglows from GROND and Swift/UVOT
• GRB 090313 and the Origin of Optical Peaks in GRB Light Curves: Implications for Lorentz Factors and Radio Flares
• GRB 021004 modelled by multiple energy injections
• The Swift/Fermi GRB 080928 from 1 eV to 150 keV
• Energy Injection Episodes in Gamma Ray Bursts: The Light Curves and Polarization Properties of GRB 021004
• The Early Optical Afterglow of GRB 030418 and Progenitor Mass Loss
• Continuous optical monitoring during the prompt emission of GRB 060111B
• Theory of photospheric emission from relativistic outflows
• GRB Flares: UV/Optical Flaring (Paper I)
• Estimates for Lorentz factors of gamma-ray bursts from early optical afterglow observations
• Prompt optical emission from residual collisions in GRB outflows
• First-year Results of Broadband Spectroscopy of the Brightest Fermi-GBM Gamma-Ray Bursts
• Is GRB afterglow emission intrinsically anisotropic ?
• Prompt emission of GRB 121217A from gamma-rays to the NIR
• Pair-dominated GeV-optical flash in GRB 130427A
• Spectral Softening in X-ray Afterglow of GRB 130925A as Predicted by Dust Scattering Model
• A Unified Model of the Prompt Optical Emission of Gamma-Ray Bursts

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• The 3rd Fermi GBM Gamma-Ray Burst Catalog: The First Six Years
• Physics of Gamma-Ray Bursts Prompt Emission
• Effects of Fall-Back Accretion on Proto-Magnetar Outflows in Gamma-Ray Bursts and Superluminous Supernovae
• The X-shooter GRB afterglow legacy sample (XS-GRB)
• A Comparative Study of Long and Short GRBs. I. Overlapping Properties
• Dust in the wind: the role of recent mass loss in long gamma-ray bursts
• The sharpness of gamma-ray burst prompt emission spectra
• The Optical/NIR afterglow of GRB 111209A: Complex yet not Unprecedented
• A comprehensive statistical study on gamma-ray bursts
• Four GRB-Supernovae at Redshifts between 0.4 and 0.8
• Super-solar metallicity at the position of the ultra-long GRB130925A
• A Large Catalogue of Multi-wavelength GRB Afterglows I: Color Evolution And Its Physical Implication
• Limits on optical polarization during the prompt phase of GRB 140430A
• The unusual radio afterglow of the ultra-long gamma-ray burst GRB 130925A
• The ultra-long GRB 220627A at z=3.08
• ALMA CO Observations of the Host Galaxies of Long-duration Gamma-ray Bursts. I: Molecular Gas Scaling Relations
• Swift/UVOT: 18 Years of Long GRB Discoveries and Advances
• Possible correlations between the emission properties of short GRBs and their offsets from the host galaxies
• ALMA Host galaxy observation of the off-axis Gamma-Ray Burst XRF020903
• The Spectral Sharpness Angle of Gamma-ray Bursts
• Is Bremsstrahlung A Possible Mechanism to Explain the Thermal Feature in the GRB 130925A X-ray Afterglow?