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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"

15678 results found.

  1. GRB 060313: Possible optical counterpart
  2. GRB 060313, SMARTS optical/IR observations
  3. GRB060313: optical and near infrared observations with REM
  4. GRB 060312: ROTSE-III Optical Limits
  5. GRB060218: analysis of the XMM-Newton observation
  6. GRB 060218: RTT150 optical observations
  7. GRB060223b: optical limit
  8. GRB060218/SN 2006aj: optical observation in V
  9. GRB060218/SN 2006aj: optical observation
  10. GRB 060121: HST observations
  11. GRB 060218/SN 2006aj: K-380 optical observations
  12. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  13. GRB200618: optical polarimetry and photometry
  14. GRB 060218/SN 2006aj: ABT observations
  15. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  16. GRB 060218 : Radio upper limits from GMRT
  17. GRB 060218/SN 2006aj: WIRO optical observations
  18. GRB 060218/SN 2006aj: RBO optical observations
  19. GRB 060204B: GETS early limit
  20. GRB 060223A:Xinglong optical limits
  21. GRB 060223B: ART optical limits
  22. GRB 060218: rebrightening
  23. Correction to GCN 4816 on GRB060218
  24. GRB 060218/SN 2006aj: optical observations
  25. GRB060218: Optical brightening in V and R
  26. GRB 060223: Keck redshift
  27. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  28. Spectral properties of GRB060218/SN2006aj
  29. GRB 060218: rebrightening
  30. GRB 060218: emergence of the underlying SN spectrum
  31. GRB 060218: Decline in r-band flux
  32. GRB 060218: spectroscopic observations
  33. GRB060218: Optical Spectroscopy of GRB-SN
  34. GRB060218: VLT spectroscopy
  35. GRB 060218: Optical Observations at Xinglong Obs.
  36. GRB060218: UV Detection and Light Curves
  37. GRB060218: Radio Afterglow Discovery
  38. GRB 060218: MDM Redshift
  39. GRB 060218: optical/nIR observations at La Palma
  40. Oddball GRB 060218, transient or GRB?
  41. Brightening of the Optical Counterpart of the Possible GRB 060218
  42. GRB 060218: MDM Observations
  43. GRB 060218A: ROTSE-III Possible Optical Flare
  44. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  45. GRB 060213: optical afterglow not confirmed
  46. Swift UVOT observations of GRB060213
  47. GRB 060213: optical afterglow candidate
  48. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  49. GRB 060211b: WIRO NIR Observations
  50. GRB060213:_MASTER_optical_observation
  51. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  52. GRB 060210: Radio Observations
  53. GRB 060211a: WIRO NIR Observations
  54. GRB060211B: REM optical and NIR observations
  55. GRB060121: optical observations
  56. GRB060110: optical observations
  57. GRB060105: optical observations
  58. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  59. GRB 060206: SOAR Detections
  60. GRB 050826: Optical Afterglow and Host Galaxy
  61. GRB060211b: optical observation
  62. GRB 060210: Optical Observations
  63. GRB060211: Faulkes North observation
  64. GRB 060211: ROTSE-III Optical Limits
  65. GRB060210: Swift XRT Refined Analysis
  66. GRB060206, optical observations
  67. GRB 060210 : Xinglong and Lulin optical limit
  68. GRB060210: Optical Observations
  69. GRB060210: Gemini absorption spectroscopy
  70. GRB060210: Early Optical Observations
  71. GRB 060210: optical evolution
  72. GRB060210: Optical afterglow
  73. GRB060209: RTT150 optical observations
  74. GRB 060209 : TAROT optical observation
  75. GRB060209A: MASTER optical observation
  76. GRB 060206: WSRT Radio Observations
  77. GRB 060206: More PROMPT Detections
  78. GRB 060121 : WIDGET Pre-trigger limit
  79. GRB 060206: optical observations at Asiago
  80. Orphan GRB Afterglow candidate
  81. GRB 060206: Subaru/FOCAS optical spectroscopy
  82. GRB 060206: Super-LOTIS observations
  83. GRB060204A: Swift/UVOT observations
  84. GRB 060206 : Lulin optical observations
  85. GRB060206: Swift XRT Refined Analysis
  86. GRB060206: Liverpool Telescope observation
  87. GRB060206: P60 Optical Observations
  88. GRB060206: Swift XRT Position
  89. GRB 060206: RAPTOR observations of afterglow candidate variability.
  90. GRB 060206: High redshift burst
  91. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  92. GRB060206: Optical afterglow
  93. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  94. GRB060203: WHT Z-band observations
  95. GRB060204C: optical observation
  96. GRB 060204B: BVRi-band detections of optical afterglow
  97. GRB 060204A: FRAM optical observations
  98. GRB 060204C: optical observations
  99. GRB 060204B: ART early limit
  100. GRB060204B: Swift XRT Team Refined Analysis

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