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"

2803 results found.

  1. GRB 160409A found in Swift BAT ground analysis
  2. GRB 160408A: TLS Tautenburg observations
  3. GRB 160408A: Swift/UVOT Upper Limits
  4. GRB 160324A: CALET Gamma-Ray Burst Monitor detection
  5. GRB 160321A: Possible RATIR Optical and NIR Detections
  6. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  7. GRB 160310A: Swift/UVOT Upper Limits
  8. Konus-Wind observation of GRB 160310A (possible ultra-long GRB?)
  9. GRB 160307A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  10. GRB 160310A: NOT optical observations
  11. GRB 160303A: GTC imaging of possible host galaxy
  12. GRB 160303A: Observations from T150 OSN
  13. GRB 160303A: McDonald 2.1m CQUEAN Detection
  14. GRB160228A: Further analyses on spectral lag and extended emission
  15. GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 follow up observations
  16. GRB 160223B: Khureltogot optical observations
  17. Swift Trigger 674752 is likely a noise fluctuation in the direction of IGR17488-3253
  18. GRB 160131A: second epoch observations with the GMRT
  19. Low frequency GMRT observations of GRB 160131A
  20. GRB 160131A: RATIR Optical Observations
  21. LIGO/Virgo G211117: MASTER OTs 26.XII.2015 - 01.I.2016
  22. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  23. LIGO/Virgo G211117: MASTER Observations and Inspection + OT
  24. LIGO/Virgo G211117: INTEGRAL was inactive at the time of the event
  25. LIGO/Virgo G211117: MASTER possible OT detection at the begining of inspection
  26. GRB 151225A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  27. GRB 151221A: INTEGRAL detection of a short burst or possible SGR
  28. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  29. GRB 151122A: Swift detection of a burst
  30. Swift Trigger 664610: is unlikely a GRB
  31. 610 MHz detection of GRB 151027A with the GMRT
  32. GMRT radio detection of GRB 151027A
  33. GRB 151111A: GROND marginal detection of a afterglow candidate
  34. GRB 151111A: LCOGT-FTS afterglow observations
  35. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  36. GRB 151107A: Further investigation of the source nature
  37. GRB 151107A: Swift detection of a possible burst
  38. GRB 151027A: GMG observation
  39. GRB 151027A: P60 afterglow confirmation and rebrightening
  40. LIGO/Virgo G194575: CQUEAN/LOAO observations
  41. Possible Fermi-LAT Gamma-ray counterpart for LIGO/Virgo G194575
  42. LIGO/Virgo G194575: Mini-MegaTORTORA observations
  43. LIGO Virgo G194575: TZAC TAROT observations
  44. Trigger 657564 / GRB 151004A: Swift/UVOT Upper Limits
  45. Swift Trigger 657564: XRT prompt analysis
  46. LIGO/Virgo G184098: MASTER OTs detection and Scenario Machine prediction
  47. LIGO/Virgo G184098: spectral classification of PS15cci
  48. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  49. GRB 150906B: Further analysis of the Konus-Wind data
  50. ANTARES neutrino detection: ANU 2.3m and Kepler K2 Observations of the Swift x-ray source
  51. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  52. ANTARES neutrino detection and possible Swift X-ray counterpart
  53. GRB 150818A: possible SN rise in light curve of Mondy observations
  54. Swift Trigger 652046 is probably not a GRB
  55. GRB 150728A: FTN observations
  56. GRB 150720A: Swift-XRT refined Analysis
  57. Swift Trigger 649706: a possible GRB or bright Galactic transient
  58. Swift-XRT observations of GRB 150710A
  59. GRB 150710A: RATIR Observations
  60. Swift Trigger 648422: Swift-XRT observations
  61. Trigger 648422: Swift possible detection of a source in NGC4552
  62. Swift Trigger 645340: a possible GRB
  63. V404 Cyg: Fermi GBM observations
  64. GRB 150518A: possible SN observations
  65. Swift trigger 642453 is not an astrophysical source
  66. Swift Trigger 642453: a possible GRB
  67. GRB 150518A: MAXI-GSC further analysis
  68. GRB 150518A: AMI 15 GHz detection of possible radio counterpart
  69. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  70. GRB 150518A: SAO RAS optical observations
  71. Swift Trigger 639636: a possible GRB
  72. GRB 150413A: AMI 15 GHz confirmation of radio counterpart
  73. GRB150418A: Swift/UVOT did not detect a new source
  74. GRB 150413A: AMI 15 GHz detection of possible radio counterpart
  75. GRB 150407A: optical observations
  76. GRB 150407A: Swift detection of a possible burst
  77. Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
  78. GRB 150323C: additional optical observations in Mondy
  79. GRB 141121A: GMG observation
  80. GRB 150323C: possible host galaxy detection
  81. Swift Trigger 635306 is probably not an astrophysical source
  82. GRB 150220A, the review of the sky area in plate archives
  83. GRB 150314A: Fermi-LAT detection
  84. GRB 150311A: MAXI/GSC possible afterglow detection
  85. GRB 150309A: Swift-BAT refined analysis
  86. GRB 150301C: VLA Observations
  87. Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
  88. GRB 150301C : (Swift trigger 633105) Swift observations
  89. Swift Trigger 633173 is probably not an astrophysical source
  90. Trigger 633105 is likely not a GRB
  91. GRB 150213B, the review of the sky area in plate archives
  92. GRB 150212A, the review of the sky area in plate archives
  93. GRB 150206B: Fermi GBM detection
  94. GRB 150204A: Swift/UVOT Upper Limits
  95. GRB 150201A: Fermi GBM observation
  96. GRB 150120A: 9.8 GHz VLA upper limit
  97. GRB 150120A: possible AMI 15 GHz detection
  98. GRB 150110B: AMI 15 GHz detection of possible radio counterpart
  99. GRB 150101B/Swift J123205.1-105602, deep VLT observations
  100. Radio upper limit on the GRB 141121A with the GMRT

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