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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"

37733 results found.

  1. GRB 070411, further deep LBT photometry
  2. GRB 070411: Late-time Keck imaging
  3. GRB 070411 : Planned XMM-Newton observation
  4. GRB070419B: Suzaku WAM observation of the prompt emission
  5. GRB 070420, SMARTS optical/IR afterglow observations
  6. GRB 070411, deep LBT photometry
  7. GRB 070420: pseudo-z~1.56 from spectral parameters of the prompt
  8. Konus-Wind observation of GRB 070420
  9. GRB 070411: break in the optical light curve
  10. GRB 070420 Swift-BAT Refined Analysis
  11. GRB070419A: Kuiper Optical detection
  12. GRB070419a: Swift UVOT observations
  13. GRB 070419A: MARGE Observations
  14. GRB 070420: optical rebrightening observed at Mt. John
  15. GRB 070420: Swift XRT refined analysis
  16. GRB070420: Swift UVOT continuing observations
  17. GRB 070411: BART early limit
  18. GRB 070420: Faulkes Telescope South Observations
  19. GBR 070419A: Swift/XRT refined analysis
  20. GRB 070420: TAROT La Silla observatory optical observations
  21. GRB 070420: NIR and optical afterglow confirmed
  22. GRB 070420: Swift detection of a burst with optical afterglow
  23. GRB 070419A: MITSuME Okayama Observations
  24. GRB 070419A: Early Super-LOTIS Observations
  25. GRB 070419B, Swift-BAT refined analysis
  26. GRB 070419A Swift-BAT Refined Analysis
  27. GRB 070419A: RAPTOR Detection of Early Emission
  28. GRB 070419B: Swift XRT refined analysis
  29. GRB 070419: Keck/LRIS Absorption Redshift
  30. GRB 070419B: optical afterglow confirmation
  31. GRB 070419A, Optical observations
  32. GRB 070411: Deep VLT detection
  33. GRB070419 - SDSS Pre-Burst Observations
  34. GRB 070419A: SARA observations
  35. GRB 070419A: NAYUTA Optical Observation
  36. GRB 070419A: Faulkes Telescope North Optical Observations
  37. GRB 070419B optical afterglow candidate
  38. GRB 070419A: Optical and IR observations with KANATA
  39. GRB 070419B: optical afterglow candidate
  40. GRB 070419A: Lulin Optical observation
  41. GRB070419A, optical observation
  42. Infrared detection of GRB070419A with UKIRT
  43. GRB 070419A: Kiso Optical observation
  44. GRB070330: Correction to UVOT position
  45. GRB 070419: P60 Confirmation of Optical Afterglow
  46. GRB 070419B: Swift detection of a burst
  47. GRB 070419 optical afterglow candidate
  48. GRB 070419A: ROTSE-III Optical Limits
  49. GRB 070419: Swift detection of a burst
  50. Swift-BAT Trigger 276045 is a Cosmic Ray Shower event
  51. GRB 070418: Optical and IR observations with KANATA
  52. Trigger 276045: Swift detection of a possible burst
  53. GRB 070406: Swift XRT refined analysis
  54. IBAS Alert n.4202: not a real GRB
  55. GRB 070318, SMARTS optical/IR afterglow observations
  56. GRB 070411: TLS data shows plateau, flares
  57. GRB070412: UKIRT-WFCAM JHK upper limits
  58. GRB070412: Swift UVOT observations
  59. IBAS Alert n.4199: Not a GRB
  60. GRB 070411: Swift/UVOT observations
  61. GRB 070412, Swift-BAT refined analysis
  62. GRB 070412 Liverpool Telescope optical limit
  63. GRB 070411: Optical photometry at Crni Vrh
  64. GRB 070412: Swift-XRT refined analysis
  65. GRB 070411: Swift-XRT refined analysis
  66. GRB 070412: further reanalysis of NOT images
  67. GRB 070412: Optical observations at Crni Vrh
  68. GRB 070411: OA redshift
  69. GRB 070412: Swift-XRT refined position
  70. GRB 070412: further NOT observations
  71. GRB 070412: Gemini/GMOS afterglow candidate
  72. GRB 070412: IAC80 optical afterglow candidate
  73. GRB 070411: Magellan/Clay photometry
  74. GRB 070411: Magellan/IMACS photometry
  75. GRB 070412: NOT observations
  76. GRB 070412: Nearby bright galaxy
  77. GRB 070411, Swift-BAT refined analysis
  78. GRB 070412: Swift detection of a burst
  79. GRB 070411: IAC80 optical observations
  80. GRB 070411 : Liverpool Telescope Observations
  81. GRB 070411: Optical observations at Crni Vrh
  82. GRB 070411: ROTSE-III Detection of Optical Counterpart
  83. GRB 070411: Tautenburg RRM Afterglow Confirmation
  84. GRB 070411: Swift detection of a burst with optical afterglow
  85. GRB 070406: "Star" in XRT error circle S2 is an AGN?
  86. GRB 070406: Swift XRT team further analysis
  87. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  88. GRB 070406: Bright galaxy in XRT error circle is a quasar
  89. GRB 070406, Swift-BAT refined analysis
  90. GRB 070406: Correction to the optical candidate in GCN6253
  91. GRB 070406: Gemini South Imaging and XRT analysis
  92. GRB070406: Swift UVOT observations
  93. GRB 070406: further analysis of NOT images.
  94. Short GRB 070406 - Possible Bright Host Galaxy
  95. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  96. GRB 070406: NOT observations
  97. GRB 070406: Optical candidate
  98. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  99. GRB 070406: SARA upper limit
  100. GRB 070406: Xinglong TNT optical Upper Limit

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