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"

11752 results found.

  1. EP240930a: Liverpool Telescope observations
  2. GRB 241002A: Swift-XRT refined Analysis
  3. GRB 241002B: GOTO optical counterpart candidate
  4. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  5. Fermi GRB 241002B: Global MASTER-Net observations report
  6. GRB 241002A: Swift detection of a burst
  7. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  8. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  9. EP240930a: GOTO optical upper limits
  10. EP EP240930a: Global MASTER-Net observations report
  11. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  12. GRB 240929A : Leavitt Observatory optical upper limit
  13. Fermi GRB 240930B: Global MASTER-Net observations report
  14. Fermi GRB 240930A: Global MASTER-Net observations report
  15. GRB 240929A long GRB detected by INTEGRAL
  16. Fermi GRB 240929A: Global MASTER-Net observations report
  17. Konus-Wind detection of GRB 240912A
  18. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  19. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  20. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  21. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  22. Konus-Wind detection of GRB 240905B
  23. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  24. EP240918b and EP240918c: EP-FXT follow-up observations
  25. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  26. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  27. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  28. Konus-Wind detection of GRB 240918B
  29. IPN triangulation of GRB 240918B
  30. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  31. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  32. LIGO/Virgo S240919bn: GOTO optical upper limits
  33. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  34. GRB 240918B: AstroSat CZTI detection
  35. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  36. EP240919a: EP-FXT follow-up observation update
  37. EP240919a / GRB 240919A: Mondy optical upper limit
  38. EP240919a: Optical upper limit with Kinder observations
  39. GRB 240919A / EP240919a: SVOM/GRM observation
  40. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  41. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  42. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  43. EP EP240919a: Global MASTER-Net observations report
  44. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  45. EP240919a: NOT and Gemini optical observations
  46. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  47. EP240919a: EP-WXT detection of a fast X-ray transient
  48. GRB 240918B: Fermi GBM Detection
  49. EP240918a: EP observation update
  50. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  51. Fermi GRB 240918A: Global MASTER-Net observations report
  52. GRB 240918A: Fermi GBM Final Real-time Localization
  53. EP EP240918a: Global MASTER-Net observations report
  54. EP240918a: YAHPT Optical Upper Limit
  55. EP240918a: Optical upper limits with Kinder observations
  56. EP240918a: an X-ray transient detected by Einstein Probe
  57. GRB 240916A: NOT optical observation
  58. LIGO/Virgo/KAGRA S240915b: NED Galaxies in the Localization Volume
  59. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  60. EP EP240913a: Global MASTER-Net observations report
  61. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  62. Fermi Gamma-ray Burst Monitor trigger 748124309/240915846 is not a GRB
  63. GRB 240914B: AstroSat CZTI detection
  64. EP240913A / GRB 240913C: AstroSat CZTI detection
  65. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  66. EP240913a: EP-WXT detection of a fast X-ray transient
  67. GRB 240913B: Fermi GBM Final Real-time Localization
  68. GRB 240912A: Swift-XRT refined Analysis
  69. GRB 240912A: NOT optical spectroscopy
  70. GRB 240912A: Swift detection of a burst with an optical counterpart
  71. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  72. GRB 240825A: 7DT Optical Upper Limit
  73. LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
  74. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  75. EP240908a: Updates on the WXT detection result around the trigger time
  76. Fermi GRB 240910A: Global MASTER-Net observations report
  77. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  78. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  79. GRB 240905E: GIT optical upper limit
  80. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  81. GRB 240905B: Fermi-LAT detection
  82. GRB 240905E: SVOM/C-GFT optical upper limit
  83. GRB 240902B: AstroSat CZTI detection of a long burst
  84. GRB 240905E: Swift-XRT refined Analysis
  85. GRB 240902A: AstroSat CZTI detection of a long burst
  86. GRB 240905D: AstroSat CZTI detection
  87. GRB 240905B: AstroSat CZTI detection and localization
  88. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  89. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  90. GRB 240825A: MeerLICHT afterglow detection
  91. Fermi trigger No 746923430: Global MASTER-Net observations report
  92. GRB 240828B: Mephisto optical upper limit
  93. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  94. GRB 240825A: MeerKAT detection
  95. GRB 240828B: J-band upper limit from WINTER
  96. GRB 240828B: GWAC-F50A optical upper limit
  97. GRB 240828B: SAO RAS optical upper limit
  98. Fermi trigger No 746587425: Global MASTER-Net observations report
  99. GRB 240828A: Swift-XRT afterglow detection
  100. GRB 240828A: Fermi-LAT detection

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov