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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"

11404 results found.

  1. GRB 240727A: VIRT Optical Upper Limit
  2. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  3. Fermi trigger No 750788395: Global MASTER-Net observations report
  4. Fermi GRB 241016B: Global MASTER-Net observations report
  5. Fermi GRB 241016A: Global MASTER-Net observations report
  6. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  7. GRB241013A: REM observations
  8. GRB 241013A: a long GRB detected by INTEGRAL
  9. LIGO/Virgo/KAGRA S241011k: NED Galaxies in the Localization Volume
  10. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  11. GRB 241011A: Fermi GBM Final Real-time Localization
  12. GRB 241010A: Swift-XRT refined Analysis
  13. Fermi trigger No 750211959: Global MASTER-Net observations report
  14. Fermi trigger No 750291012: Global MASTER-Net observations report
  15. GRB 241010A: Swift detection of a burst with an optical counterpart
  16. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  17. GRB 241008A: Fermi-LAT detection
  18. GRB 241002B: Swift-XRT afterglow detection
  19. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  20. GRB 240910A: LBT optical observations
  21. GRB 241006A: Swift-XRT refined Analysis
  22. IceCube Alert 241006.94: Global MASTER-Net observations report
  23. GRB 241006A: Swift detection of a burst
  24. Swift GRB241006.91: Global MASTER-Net observations report
  25. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  26. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  27. Fermi trigger No 749693019: Global MASTER-Net observations report
  28. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  29. Konus-Wind detection of GRB 240926A
  30. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  31. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  32. EP240930a: Liverpool Telescope observations
  33. GRB 241002A: Swift-XRT refined Analysis
  34. GRB 241002B: GOTO optical counterpart candidate
  35. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  36. Fermi GRB 241002B: Global MASTER-Net observations report
  37. GRB 241002A: Swift detection of a burst
  38. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  39. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  40. EP240930a: GOTO optical upper limits
  41. EP EP240930a: Global MASTER-Net observations report
  42. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  43. GRB 240929A : Leavitt Observatory optical upper limit
  44. Fermi GRB 240930B: Global MASTER-Net observations report
  45. Fermi GRB 240930A: Global MASTER-Net observations report
  46. GRB 240929A long GRB detected by INTEGRAL
  47. Fermi GRB 240929A: Global MASTER-Net observations report
  48. Konus-Wind detection of GRB 240912A
  49. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  50. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  51. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  52. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  53. Konus-Wind detection of GRB 240905B
  54. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  55. EP240918b and EP240918c: EP-FXT follow-up observations
  56. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  57. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  58. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  59. Konus-Wind detection of GRB 240918B
  60. IPN triangulation of GRB 240918B
  61. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  62. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo S240919bn: GOTO optical upper limits
  64. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  65. GRB 240918B: AstroSat CZTI detection
  66. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  67. EP240919a: EP-FXT follow-up observation update
  68. EP240919a / GRB 240919A: Mondy optical upper limit
  69. EP240919a: Optical upper limit with Kinder observations
  70. GRB 240919A / EP240919a: SVOM/GRM observation
  71. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  72. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  73. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  74. EP EP240919a: Global MASTER-Net observations report
  75. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  76. EP240919a: NOT and Gemini optical observations
  77. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  78. EP240919a: EP-WXT detection of a fast X-ray transient
  79. GRB 240918B: Fermi GBM Detection
  80. EP240918a: EP observation update
  81. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  82. Fermi GRB 240918A: Global MASTER-Net observations report
  83. GRB 240918A: Fermi GBM Final Real-time Localization
  84. EP EP240918a: Global MASTER-Net observations report
  85. EP240918a: YAHPT Optical Upper Limit
  86. EP240918a: Optical upper limits with Kinder observations
  87. EP240918a: an X-ray transient detected by Einstein Probe
  88. GRB 240916A: NOT optical observation
  89. LIGO/Virgo/KAGRA S240915b: NED Galaxies in the Localization Volume
  90. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  91. EP EP240913a: Global MASTER-Net observations report
  92. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  93. Fermi Gamma-ray Burst Monitor trigger 748124309/240915846 is not a GRB
  94. GRB 240914B: AstroSat CZTI detection
  95. EP240913A / GRB 240913C: AstroSat CZTI detection
  96. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  97. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  98. EP240913a: EP-WXT detection of a fast X-ray transient
  99. GRB 240913B: Fermi GBM Final Real-time Localization
  100. GRB 240912A: Swift-XRT refined Analysis

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