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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"

45423 results found.

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

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