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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 101011A: Enhanced Swift-XRT position
  2. GRB 101011A: Swift-BAT refined analysis
  3. GRB 101011A: Swift detection of a burst
  4. GRB 101008A: Fermi GBM observation
  5. GRB 101008A: MASTER prompt optical observations (correction to GCN#11328)
  6. GRB 101008A: MASTER prompt optical observations
  7. GRB 101008A: Swift-BAT refined analysis
  8. GRB101008A, GROND detection of a fading afterglow
  9. GRB 101008A: Swift-XRT refined analysis
  10. GRB 101008A: SAO RAS optical observations
  11. GRB 100915 optical upper limit
  12. GRB 101008: Swift/UVOT Upper Limits
  13. GRB 101008A: Enhanced Swift-XRT position
  14. GRB 101008A: 1.23m CAHA optical observations
  15. GRB 101008A: Swift/XRT Detection of an Afterglow with no UVOT Counterpart
  16. GRB 101008A: Swift detection of a burst
  17. GRB 100728B: X-shooter redshift
  18. Refined analysis shows Swift Trigger 435520 is not a GRB
  19. Swift Trigger 435520 is probably not a GRB
  20. GRB 100925A / MAXI J1659-152: MASTER optical observations
  21. GRB 100924A: Suzaku WAM observation of the prompt emission
  22. GRB 100928A, Swift-BAT refined analysis
  23. GRB 100924A: Fermi GBM observation
  24. GRB 100928A: Swift detection of a burst
  25. GRB 100925A / MAXI J1659-152: WSRT Radio and Polarization Detection
  26. GRB 100925A / MAXI J1659-152: Optical observation with the Kottamia 188cm telescope
  27. GRB100925A/MAXI J1659-152: X-shooter identification as an X-ray binary
  28. GRB100925A/MAXI J1659-152 MITSuME Ishigakijima and Okayama Optical Observation
  29. GRB 100925A / MAXI J1659-152: SARA-S Observations
  30. GRB 100925A/MAXI J1659-152: Submm observations from APEX
  31. GRB100925A/MAXI J1659-152: Galactic origin from SED analysis
  32. GRB 100925A/MAXI J1659-152 - NOT optical observations
  33. GRB 100925A / MAXI J1659-152: BOOTES-2/TELMA and IAC80 optical observations
  34. MAXI J1659-152: Swift-BAT refined analysis (triggers 434928 and 434931)
  35. GRB 100925A: Nearby DSS Source - SN-GRB or new Galactic transient?
  36. GRB100925A UVOT afterglow
  37. GRB 100924A: GROND detection of an optical/NIR afterglow
  38. GRB 100925A: Swift detection of a burst
  39. GRB 100924A: Swift-BAT refined analysis
  40. GRB 100924A: Swift detection of a burst
  41. GRB 100917A: TAROT La Silla observatory optical observations
  42. GRB 100915A: TAROT Calern observatory optical observations
  43. GRB100906A: Ashra-1 observation of early optical emission
  44. GRB 100916A: Fermi GBM detection
  45. GRB 100917A: Swift-BAT refined analysis
  46. GRB 100917A: Swift detection of a burst
  47. GRB100915A: MITSuME Ishigakijima Optical upper limits
  48. GRB 100915B: GRT Optical Observation
  49. GRB 100915A: GRT Optical Observation
  50. GRB 100915B: Fermi GBM observation
  51. GRB 100915A: Correction to Swift-BAT refined analysis
  52. GRB 100915A: Swift/UVOT Upper Limits
  53. GRB 100915A: Swift-BAT refined analysis
  54. GRB 100915A: Swift-XRT refined analysis
  55. GRB 100915A: Enhanced Swift-XRT position
  56. GRB 100915B: a long GRB detected by INTEGRAL
  57. GRB 100915A: Swift detection of a likely burst
  58. GRB 100910A: Fermi GBM detection
  59. Swift-BAT trigger 433953 is not a burst
  60. Swift BAT Trigger 433953 probably not a GRB
  61. GRB100909A: MITSuME Ishigakijima Optical upper limits
  62. GRB 100909A: Swift/UVOT observations
  63. GRB 100901A: errata of GRB name in GCN 11270
  64. GRB 100901A: optical observations in Mondy and R-light curve
  65. GRB100909A: NOT optical afterglow confirmation
  66. GRB 100909A: Swift-XRT refined analysis
  67. GRB 100906A: optical observations at Mt.Terskol
  68. GRB 100901A: optical observation in Maidanak, break confirmation
  69. GRB 100909A: Faulkes Telescope North afterglow candidate
  70. GRB 100909A: ROTSE-III Optical Limits
  71. GRB 100909A: Planned XMM-Newton observation
  72. GRB 100902A : Confirmation of afterglow and re-brightening with CFHT r’-band imaging
  73. GRB 100909A: Swift target of opportunity observation
  74. GRB 100909A: a long GRB detected by INTEGRAL
  75. GRB100906A: detection at 15GHz
  76. GRB100901A: IAO optical upper limits at 4 days after the burst
  77. EVLA detection of radio afterglow of GRB100901A
  78. GRB 100901A: Confirmation of WSRT Radio Detection
  79. GRB 100901A: CrAO optical observations
  80. GRB 100906A: RTT150 optical observations
  81. GRB 100906A: GRAS-007 optical observations
  82. GRB100906A: R band observations
  83. Konus-Wind observation of GRB 100906A
  84. GRB100906A: non-detection at 15GHz
  85. GRB100906A: Optical observations at IAO
  86. GRB 100906A: Fermi GBM observation
  87. GRB 100906A: TLS Monitoring
  88. GRB 100901A: TLS Detection at 5.5 days
  89. GRB 100906A: Observations at the Virtual Telescope
  90. GRB 100906A: Swift-XRT refined analysis
  91. GRB 100906A: Enhanced Swift-XRT position
  92. GRB 100906A: Swift/UVOT Observations
  93. GRB100906A: Errata of MITSuME Okayama about observation time
  94. GRB100906A: MITSuME Okayama Optical Observation
  95. GRB 100906A: Ondrejov 65cm observations
  96. GRB 100906A: TLS Multicolor Observations
  97. GRB 100905A: Swift/UVOT Upper Limits
  98. GRB 100901A: TLS observations, SDSS calibration, decay slope
  99. GRB 100906A: MASTER preliminary prompt+afterglow lc
  100. GRB 100901A: ISON-NM optical observations

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