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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"

20967 results found.

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

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