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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"
  1. GRB 080319C: AGILE-MCAL observation of the prompt emission
  2. GRB 080319B: Hobby-Eberly Telescope Spectroscopy
  3. GRB 080319D: MASTER-VWF-Kislovodsk optical observation
  4. GRB 080319C: MASTER-VWF-Kislovodsk optical observation
  5. GRB 080319D: Swift detection of a burst with a possible optical afterglow
  6. GRB 080319B: TORTORA synchronous observation
  7. VLT/UVES redshift of GRB 080319B from FeII fine-structure lines
  8. GRB 080319A/B/C: INTEGRAL SPI-ACS light curves available
  9. GRB 080319B: Enhanced Swift-XRT position
  10. GRB 080319A: Enhanced Swift-XRT position
  11. GRB 080319A, Swift-BAT refined analysis
  12. GRB 080319B: REM early data
  13. GRB 080319b light curve by Pi-of-the-Sky
  14. VLT/UVES redshift of GRB 080319B
  15. GRB 080319C: Early Super-LOTIS Observations
  16. GRB 080319C: Swift detection of a burst with an optical afterglow
  17. GRB 080319C: KAIT OA candidate
  18. GRB 080319A: REM observations
  19. GRB 080319b prompt optical observation by Pi-of-the-Sky
  20. GRB 080319B: Change in power law decay index
  21. GRB 080319B: Gemini-South Spectroscopy
  22. GRB 080319A: optical observations at the NOT
  23. GRB0 080319B : LOAO optical observation
  24. GRB 080319b: Early IR Imaging from PAIRITEL
  25. GRB080319B Liverpool Telescope optical afterglow candidate
  26. GRB 080319B: Super-LOTIS Detection of a Bright OT
  27. GRB 080319B: REM observations
  28. GRB 080319B: KAIT OA
  29. GRB080319A: P60 Optical Afterglow Observations
  30. GRB 080319B: UVOT Position
  31. GRB 080319B: Swift detection of an intense burst with a bright optical counterpart
  32. GRB 080319A: Swift detection of a burst
  33. Swift Trigger 306745 is not a GRB
  34. Swift Trigger 306616 is not a GRB
  35. GRB080310, LBT and MDM photometry
  36. GRB080315: Bok Optical Observations
  37. Swift/UVOT observations of GRB 080315
  38. Swift trigger 306323: Swift-BAT/XRT refined analysis
  39. SAX J1818.6-1703: Swift detection (trigger 306379)
  40. GRB 080315: Optical observations
  41. GRB 080315: TAROT Calern observatory optical observations
  42. GRB 080315: Swift detection of a possible burst
  43. GRB080310 : Lulin Optical observations
  44. GRB080310, unusual slow decay in the optical
  45. GRB 080310: GAO 150cm telescope Optical Observation
  46. GRB080310 : Optical observations by LOAO and Lulin
  47. GRB 080310: ROTSE-III Observations of Optical Counterpart
  48. GRB080310: Optical observation by MITSuME telescope
  49. GRB080310, optical observations with the LBT
  50. GRB 080307: GAO 150cm telescope Optical Observation
  51. GRB 080229A: GAO 150cm telescope Optical Observation
  52. GRB 080310: PAIRITEL detection and PAIRITEL+KAIT+UVOT SED
  53. GRB 080307: NIR upper limit
  54. GRB 080229: NIR upper limit
  55. GRB 080310: early RAPTOR multicolor observations
  56. GRB 080310, Swift-BAT refined analysis
  57. GRB080210: optical observations
  58. GRB080307: optical upper limit
  59. GRB 080310: Swift-XRT refined analysis
  60. GRB 080310: Swift/UVOT Refined Analysis
  61. GRB 080310: Redshift from Keck/DEIMOS Spectra
  62. GRB 080310 - SDSS Pre-Burst Observations
  63. GRB080310 : Lulin optical observation
  64. GRB 080310: Enhanced Swift-XRT position
  65. GRB 080310: RRM optical photometry with the VLT
  66. GRB080310, detection of break in optical
  67. GRB 080310: VLT/UVES spectroscopy
  68. GRB080310, optical observations with LBT
  69. GRB 080310: Magellan redshift revision
  70. GRB 080310: Lick/Kast Spectroscopy
  71. GRB080310: Super-LOTIS suggestion of brightening
  72. GRB 080310, SMARTS optical/IR afterglow observations
  73. GRB 080310: REM observations
  74. GRB 080310: Magellan redshift
  75. GRB 080310 afterglow candidate (correction to UT time)
  76. GRB 080310: Swift detection of a burst with optical afterglow
  77. GRB 080310 afterglow candidate
  78. GRB080229, optical upper limit (Correction)
  79. GRB080307, optical upper limit
  80. GRB080307 BOAO optical afterglow observation - detection of a possible OT
  81. GRB080229, optical upper limit
  82. GRB 080307: Swift-XRT Team refined analysis
  83. GRB 080307: Swift/UVOT Upper Limits
  84. GRB 080307: Early RAPTOR Limits
  85. GRB 080307, Swift-BAT refined analysis
  86. GRB080307 - SDSS Pre-Burst Observations
  87. GRB 080307: TNT optical observation
  88. GRB080307: Optical upper limits
  89. GRB 080307: Gemini-N i-band observations - candidate afterglow
  90. GRB 080307: BOAO imaging - retraction and new limit
  91. GRB 080307: retraction of UVOT candidate
  92. GRB 080307: Enhanced Swift-XRT position
  93. GRB 080307, Preliminary Swift-BAT refined analysis
  94. GRB 080307 : BOAO optical afterglow observation
  95. GRB 080307: Optical observation with DMC/KANATA
  96. GRB 080307: Swift detection of a burst
  97. VLA possible radio detection of GRB 080229
  98. GRB 080303: Swift/UVOT follow-up of afterglow detection
  99. GRB 080303, Swift-BAT refined analysis
  100. GRB 080303: Rapid PROMPT Detections

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