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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

20964 results found.

  1. GRB 060313: Swift/UVOT Observations
  2. GRB060313:Gemini South Observations
  3. GRB060313: optical observations of the afterglow candidate
  4. GRB 060313: Possible optical counterpart
  5. GRB 060313, SMARTS optical/IR observations
  6. GRB060313: optical and near infrared observations with REM
  7. GRB060218: SARA Observations of SN2006aj
  8. GRB 060218/SN 2006aj, high resolution spectra
  9. GRB060306: APO Ks-band Imaging Observations
  10. GRB 060306: SOAR Ks Observations
  11. GRB060219: Liverpool Telescope observations
  12. GRB 060306: MAGNUM observations
  13. Swift/UVOT observations of GRB060306
  14. GRB 060306: PROMPT Observations
  15. GRB 060218: RTT150 optical observations
  16. GRB060218/SN 2006aj: optical observation in V
  17. GRB060218/SN 2006aj: optical observation
  18. GRB 060121: HST observations
  19. GRB 060223b: Swift/UVOT Upper Limits
  20. GRB 060218/SN 2006aj: K-380 optical observations
  21. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  22. GRB200618: optical polarimetry and photometry
  23. GRB 060218/SN 2006aj: ABT observations
  24. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  25. GRB 060218/SN 2006aj: WIRO optical observations
  26. GRB 060218/SN 2006aj: RBO optical observations
  27. GRB 060218: Refined analysis of the radio afterglow
  28. GRB 060223A:Xinglong optical limits
  29. Correction to GCN 4816 on GRB060218
  30. GRB 060218/SN 2006aj: optical observations
  31. GRB060218: Optical brightening in V and R
  32. GRB 060223: Keck redshift
  33. GRB 060218: rebrightening
  34. GRB 060218: emergence of the underlying SN spectrum
  35. GRB 060218: Decline in r-band flux
  36. GRB 060218: spectroscopic observations
  37. GRB 060218: Likely an underluminous GRB
  38. GRB060218: Optical Spectroscopy of GRB-SN
  39. GRB 060218: Optical Observations at Xinglong Obs.
  40. GRB060218: UV Detection and Light Curves
  41. GRB060219: SARA Observations
  42. GRB 051221B: Swift-XRT Team Refined Analysis
  43. GRB060218: Radio Afterglow Discovery
  44. GRB 060218: optical/nIR observations at La Palma
  45. GRB060219: SDSS pre-burst observations
  46. Oddball GRB 060218, transient or GRB?
  47. Brightening of the Optical Counterpart of the Possible GRB 060218
  48. GRB 060218: MDM Observations
  49. GRB 060218: Pre-burst detection of a possible host galaxy
  50. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  51. GRB060218 : SDSS pre-burst observations
  52. GRB 060213: optical afterglow not confirmed
  53. Swift UVOT observations of GRB060213
  54. GRB 060211B: Skynet Observations
  55. GRB 060213: optical afterglow candidate
  56. GRB060213: Swift XRT observations and possible afterglow candidate
  57. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  58. GRB 060211b: WIRO NIR Observations
  59. GRB060213:_MASTER_optical_observation
  60. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  61. GRB 060210: Radio Observations
  62. GRB 060211a: WIRO NIR Observations
  63. GRB060211B: REM optical and NIR observations
  64. GRB060121: optical observations
  65. GRB060110: optical observations
  66. GRB060105: optical observations
  67. GRB 060211b: P60 Observations
  68. GRB 060206: SOAR Detections
  69. GRB 050826: Optical Afterglow and Host Galaxy
  70. GRB 060210: Optical Observations
  71. GRB060206, optical observations
  72. GRB060210: Optical Observations
  73. GRB060210: Early Optical Observations
  74. GRB 060210: optical evolution
  75. GRB060210:Faulkes Telescope North Afterglow Confirmation
  76. GRB 060210: candidate afterglow
  77. GRB 060206: Swift/UVOT Observations
  78. GRB060209: RTT150 optical observations
  79. GRB 060206: near-infrared observations (JK' imaging)
  80. GRB 060206: WSRT Radio Observations
  81. GRB 060206: TTT Observations
  82. GRB 060206: More PROMPT Detections
  83. GRB 060206: Tenagra II Observations
  84. GRB060204a: Swift XRT Source is not GRB Afterglow
  85. GRB 060206: optical observations at Asiago
  86. Orphan GRB Afterglow candidate
  87. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  88. GRB 060206: Super-LOTIS observations
  89. GRB060204A: Swift/UVOT observations
  90. GRB 060206 : Lulin optical observations
  91. GRB060206: SDSS Pre-Burst Observations
  92. GRB060206: Swift XRT Refined Analysis
  93. GRB060206: P60 Optical Observations
  94. GRB 060206: KAIT observations
  95. GRB060206: SARA Detection
  96. GRB 060206: RAPTOR observations of afterglow candidate variability.
  97. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  98. GRB060206: Optical afterglow
  99. GRB060203: WHT Z-band observations
  100. GRB 060204A: FRAM optical observations

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