Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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. GRB 100725A: Swift XRT refined analysis
  2. GRB 100725B: Enhanced Swift-XRT position
  3. GRB 100725A: Enhanced Swift-XRT position
  4. GRB100725B: Faulkes Telescope North observations
  5. GRB 100725B: Swift detection of a burst
  6. GRB100725A Faulkes Telescope South observations
  7. Konus-Wind observation of GRB 100724B
  8. GRB 100725A: Prompt enhanced Swift-XRT position
  9. GRB 100725A: Swift detection of a burst
  10. GRB 100724B: Fermi LAT and GBM analysis
  11. GRB 100724B: Fermi GBM detection
  12. GRB 100724A: Swift/BAT spectral lag results
  13. GRB 100724A: Swift XRT refined analysis
  14. GRB 100724A: Enhanced Swift-XRT position
  15. GRB 100724A: Swift/UVOT observations
  16. GRB 100724A: Swift-BAT refined analysis
  17. GRB 100724A: X-shooter redshift
  18. GRB 100724A: fading afterglow seen with GROND
  19. GRB 100724A, GROND detection of an afterglow candidate
  20. GRB 100724A: Swift detection of a burst
  21. GRB 100614A: 10.4-m GTC deep-optical limit
  22. GRB 100722A: Fermi GBM detection
  23. GRB 100718A: MASTER-Net optical prompt and alert observations
  24. GRB 100719A: Swift-BAT refined analysis
  25. GRB 100719A: Swift detection of a burst
  26. GRB 100713A: optical observation in Maidanak
  27. GRB 100713A: further inspection of TNG images
  28. GRB 100713A: Swift XRT refined analysis
  29. GRB 100713A : IRSF/SIRIUS NIR upper limits
  30. Fermi GBM trigger 300794561 (100714419) is not a GRB
  31. GRB100713A: Swift/UVOT observations
  32. GRB 100713A: GROND upper limits
  33. GRB 100713A: optical upper limit
  34. GRB 100713A: TNG optical observations
  35. GRB 100713A: TELMA and 1.5m OSN optical observations
  36. GRB100713A: Swift X-ray afterglow detection
  37. GRB 100713A: a long GRB detected by INTEGRAL
  38. GRB 100707A: Suzaku WAM observation of the prompt emission
  39. Fermi GBM trigger 300370702 (100709513) is not a GRB
  40. Konus-Wind observation of GRB 100707A
  41. IPN triangulation of GRB 100707A
  42. GRB 100628A: Keck/LRIS Spectroscopy of Host Galaxy Candidate
  43. GRB 100707A: Fermi LAT detection
  44. GRB 100707A: Fermi GBM detection
  45. GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
  46. GRB 100628A: Chandra observations
  47. GRB 100628A: Swift XRT/UVOT refined analysis
  48. Tentative redshift of GRB100704A from Swift-XRT data
  49. Konus-Wind observation of GRB 100701B
  50. IPN triangulation of GRB 100701B
  51. Konus-Wind observation of GRB 100704A
  52. GRB 100703A: a short GRB detected by INTEGRAL
  53. GRB 100704A: Swift XRT refined analysis
  54. GRB 100704: Swift/UVOT Upper Limits
  55. GRB 100704A: Fermi GBM observation
  56. GRB 100704A: Swift-BAT refined analysis
  57. GRB100704A: MOA optical upper limit
  58. GRB 100704A: Enhanced Swift-XRT position
  59. GRB 100704A: Swift detection of a burst
  60. GRB 100615A: Additional Gemini/NIRI observations
  61. GRB 100526A: Gemini/NIRI afterglow confirmation and host galaxy
  62. GRB 100702A, Swift-BAT refined analysis
  63. Fermi GBM trigger 299767472 (100702531) is not a GRB
  64. GRB 100702A: Swift XRT refined analysis
  65. Swift/UVOT observations of GRB100702A - correction
  66. Swift/UVOT observations of GRB100702A
  67. GRB 100702A: Second epoch of Magellan near-IR observations and afterglow limits
  68. GRB 100701B: Fermi GBM detection
  69. GRB 100702A: Magellan near-IR observations
  70. GRB 100702A: VLT optical observations
  71. GRB 100702: ROTSE-III Optical Limits
  72. GRB 100702A: Swift detection of a short burst
  73. GRB 100615A: Chandra X-ray ToO Observation
  74. XRF 100701A : MAXI/GSC detection of a probable XRF
  75. GRB 100213B: Detection of Fading Optical Afterglow
  76. GRB 100625A: Fermi GBM detection
  77. GRB 100628A: Second epoch of Magellan near-IR observations
  78. GRB 100628A: GROND optical/NIR observations of the host candidate
  79. GRB 100628A: Gemini North Observations
  80. GRB 100628A: Coincidence of source "G1" with revised XRT error circle
  81. GRB 100628A: Swift XRT refined position
  82. GRB100625A: GROND confirmation of constant source
  83. GRB 100625A Gemini-South 2nd epoch imaging
  84. GRB100628A : MOA optical upper limit
  85. GRB 090709A: Host galaxy detection
  86. GRB 100628A: Magellan near-IR observations
  87. GRB 100628A: Swift/UVOT Upper Limits
  88. GRB100628A: RTT150 optical observations
  89. GRB 100628A: Swift XRT detection of a possible X-ray afterglow
  90. GRB 100628A: INTEGRAL SPI-ACS light curve
  91. GRB 100625A: Magellan near-IR Observations
  92. GRB 100628A: Swift-BAT refined analysis
  93. GRB 100628A: Swift detection of a short hard burst
  94. Swift-BAT trigger 426048 is not a burst
  95. GRB 100614A: CrAO optical limit
  96. GRB 100625A: Swift/UVOT Upper Limits
  97. GRB 100625A: Swift-BAT refined analysis
  98. Konus-Wind observation of GRB 100625A
  99. GRB 100625A : IRSF/SIRIUS NIR upper limit
  100. GRB 100625A: Swift-XRT Team refined analysis

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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