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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  2. GRB 241002A: Swift detection of a burst
  3. LIGO/Virgo/KAGRA S240930du: Updated Sky localization
  4. GRB 240930B: Fermi GBM Observation
  5. GRB 241001A: Swift ToO observations
  6. GRB 240930B: GRBAlpha detection
  7. GRB 240929A: GRBAlpha detection
  8. EP240930a : KAIT optical upper limit
  9. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  10. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  11. EP240930a: EP-FXT follow-up observation update
  12. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  13. EP240930a: GOTO optical upper limits
  14. GRB 240929A: SVOM/GRM observation
  15. EP EP240930a: Global MASTER-Net observations report
  16. EP240930a: EP-WXT detection of a fast X-ray transient
  17. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  18. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  19. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  20. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  21. AMON NuEM 240926A: Swift XRT Follow-up
  22. GRB 240929A : Leavitt Observatory optical upper limit
  23. Fermi GRB 240930B: Global MASTER-Net observations report
  24. GRB 240930B: Fermi GBM Final Real-time Localization
  25. IPN triangulation of GRB 240926A
  26. GRB 240825A: LBT optical observations
  27. GRB 240928A: SVOM/GRM observation
  28. Fermi GRB 240930A: Global MASTER-Net observations report
  29. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  30. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  31. GRB 240930A: Fermi GBM Final Real-time Localization
  32. Fermi trigger No 749339671: Global MASTER-Net observations report
  33. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  34. GRB 240929A long GRB detected by INTEGRAL
  35. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  36. Fermi GRB 240929A: Global MASTER-Net observations report
  37. GRB 240929A: Fermi GBM Final Real-time Localization
  38. Integral GRB240929.83: Global MASTER-Net observations report
  39. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  40. Konus-Wind detection of GRB 240912A
  41. Swift Trigger 1256950 is probably not a GRB
  42. Fermi Gamma-ray Burst Monitor trigger 749191601/240928199 is not a GRB
  43. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  44. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  45. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  46. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  47. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  48. GRB 240926A: SVOM/GRM observation
  49. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  50. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240926A
  51. Konus-Wind detection of GRB 240905B
  52. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  53. GW S240915b and S240919bn : Swift UVOT follow-up
  54. EP240919a / GRB 240919A: SVOM/VT upper limit
  55. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  56. EP240918b and EP240918c: EP-FXT follow-up observations
  57. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  58. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  59. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  60. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  61. Konus-Wind detection of GRB 240918B
  62. IPN triangulation of GRB 240918B
  63. GRB 240905B: VZLUSAT-2 detection
  64. LIGO/Virgo/KAGRA S240922df: Updated Sky localization
  65. LIGO/Virgo/KAGRA S240920dw: Updated Sky localization
  66. LIGO/Virgo/KAGRA S240921cw: Updated Sky localization
  67. LIGO/Virgo/KAGRA S240924a: Updated Sky localization
  68. LIGO/Virgo/KAGRA S240920bz: Updated Sky localization and Source Classification
  69. LIGO/Virgo/KAGRA S240923ct: Updated Sky localization and Source Classification
  70. EP trigger ID 01709059262: correction to the observation start time and source localization
  71. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  72. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  73. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo S240919bn: GOTO optical upper limits
  75. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  76. GRB 240918B: AstroSat CZTI detection
  77. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  79. EP240919a: EP-FXT follow-up observation update
  80. EP240913A/GRB 240913C: AbAO optical upper limit
  81. EP240919a / GRB 240919A: Mondy optical upper limit
  82. EP240913a/GRB 240913C: 1.6m Mephisto observations
  83. EP240918a: SVOM/VT upper limit
  84. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  85. EP240919a / GRB 240919A: REM optical and NIR upper limits
  86. EP240919a / GRB 240919A: KAIT optical upper limit
  87. EP240918b and EP240918c: Optical upper limits with Kinder observations
  88. GRB 240414A: further radio observations with the VLA
  89. EP240919a: Optical upper limit with Kinder observations
  90. GRB 240919A / EP240919a: SVOM/GRM observation
  91. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  92. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  93. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  94. EP EP240919a: Global MASTER-Net observations report
  95. GRB 240910A: radio detection with the VLA
  96. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  97. EP240919a: NOT and Gemini optical observations
  98. EP240919a: GOTO optical upper limits
  99. EP240919a: JinShan optical upper limits
  100. EP240919a is likely a GRB event (duplicate submission of 37563)

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