Skip to main content
New! BOOM Notices and Schema v7.0.0. See news and announcements

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. GRB070612A: MITSuME Okayama Observation
  2. GRB 070612A: continued SARA observations
  3. GRB 070612A: spectral lag
  4. GRB 070611: Watcher Observations
  5. Swift Trigger 282176 is Cygnus X-1
  6. GRB 070612A: MDM Observations
  7. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  8. GRB 070612B: SARA upper limit
  9. GRB 070612B, Swift-BAT refined analysis
  10. GRB 070612A, Swift-BAT refined analysis
  11. GRB 070612B: Swift-XRT refined analysis
  12. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  13. GRB 070612B: Swift/UVOT upper limits
  14. GRB 070612B: FRAM limit
  15. GRB070612B: P60 Observations
  16. GRB 070612B: KAIT limits
  17. GRB 070612A: SARA detection of possible OT
  18. GRB 070612B: Swift XRT position from downlink data
  19. GRB 070610: TAROT Calern observatory optical observations
  20. GRB 070610: MITSuME OAO optical upper limit
  21. GRB 070612B: Swift detection of a burst
  22. GRB070612 - SDSS Pre-Burst Observations
  23. GRB 070612: Swift detection of a burst
  24. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  25. GRB 070610: SARA upper limit
  26. GRB 070610: Swift-XRT refined analysis
  27. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  28. GRB 070611: Swift/UVOT Observations
  29. GRB 070611: Swift-XRT refined analysis
  30. GRB 070611, Swift-BAT refined analysis
  31. GRB 070610: Optical observations from OSN
  32. GRB 070610: Watcher Observations
  33. GRB 070611: VLT redshift
  34. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  35. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  36. GRB 070611; Swift-XRT position
  37. GRB 070611: ROTSE-III Optical Limits
  38. GRB 070611: Swift detection of a burst
  39. GRB 070610: Swift-UVOT Upper Limits
  40. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  41. GRB 070610, Swift-BAT refined analysis
  42. GRB 070610; Swift-XRT position
  43. GRB 070610: Swift detection of a burst
  44. GRB 070412: TAROT Calern observatory optical observations
  45. GRB 070411: TAROT Calern observatory optical observations
  46. GRB 070419A, deep LBT photometry and possible supernova detection
  47. GRB070520B: optical observations
  48. GRB070520: optical observation
  49. GRB070518: optical observation
  50. GRB070521: optical observation
  51. Swift/UVOT refined analysis of GRB070531
  52. GRB 070531: NOT nIR observations
  53. GRB 070531: Swift-BAT refined analysis
  54. GRB 070531: I-band observations from IAC80
  55. GRB 070531: Swift-XRT position
  56. GRB 070531: Liverpool Telescope Optical Observations
  57. GRB 070531: Swift detection of a burst
  58. GRB 070529: SARA upper limit
  59. Swift/UVOT refined analysis of GRB070529
  60. GRB 070529: MARGE Observations
  61. GRB 070529: Optical aterglow from MIRO
  62. GRB 070529: Gemini Redshift
  63. GRB 070529: Swift-XRT refined analysis
  64. GRB 070529, Swift-BAT refined analysis
  65. GRB 070529: Xinglong TNT Optical Upper Limit
  66. GRB 070529: Swift detection of a burst with an optical aterglow
  67. GRB 070412: Deep Keck imaging
  68. Swift Triggers 280447, 280450 and 280451 are invalid
  69. Swift trigger 280447 is probably a Galactic transient
  70. GRB 070518, deep LBT photometry
  71. GRB 070518: MARGE Observations
  72. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum
  73. Konus-Wind observation of GRB 070521
  74. GRB 070518: optical observation
  75. GRB070521: Second Epoch Gemini Imaging
  76. GRB070521: NIR observations
  77. GRB070520B: NIR observations
  78. GRB 070521: Swift/UVOT Upper Limits
  79. GRB 070521, optical observation
  80. GRB 070521: Swift-XRT refined analysis
  81. GRB 070521: Keck imaging
  82. GRB070521: Gemini Observations
  83. GROND upper limits of GRB 070521
  84. GRB 070521 Milagro GeV/TeV Observations
  85. GRB 070520B: SARA upper limit
  86. GRB 070520A: SARA upper limit
  87. GRB 070521: SARA upper limit
  88. GRB 070521: Subaru observations and possible host detection
  89. GRB070518: Optical/NIR observation
  90. GRB 070520B: Swift/UVOT Upper Limits
  91. GRB 070520A: Subaru Observations
  92. GRB 070521, Swift-BAT refined analysis
  93. GRB 070520A: Swift UVOT Upper Limits
  94. GRB 070520B: Swift-XRT refined analysis
  95. GRB 070521: optical limit by Pi of the Sky
  96. GRB070521: P200 Observations
  97. GRB070521 : Faulkes Telescope North Observations
  98. GRB 070521: TAROT La Silla observatory optical observations
  99. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  100. GRB070521 - SDSS Pre-Burst Observations

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov