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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"

14832 results found.

  1. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  2. GRB 241120A: GRBAlpha detection
  3. Konus-Wind detection of GRB 241117A
  4. GRB 241105A: ATCA radio detection
  5. IPN triangulation of GRB 241117A
  6. GRB 241026A: VIRT Optical Upper Limit
  7. GRB 241025A: VIRT Optical Upper Limit
  8. Konus-Wind detection of GRB 241120A
  9. GRB241120A: OHP/T193 optical observations
  10. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  11. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  12. GRB 241113A: Possible ATCA Radio detection
  13. GRB 241114B: Insight-HXMT/HE detection
  14. EP241119a: EP detection of a fast X-ray transient
  15. GRB 241120A: Fermi GBM Final Real-time Localization
  16. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  17. GRB 241119A: Fermi GBM Final Real-time Localization
  18. GRB 241115a: PRIME near-infrared upper limits
  19. GRB 241118A: Fermi GBM Final Real-time Localization
  20. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  21. GRB 241117A: Fermi GBM Detection
  22. GRB 241117B: Fermi GBM Final Real-time Localization
  23. GRB 241117A: Fermi GBM Final Real-time Localization
  24. GRB 241115A: Swift-XRT afterglow detection
  25. GRB 241115D / EP 241115a: SVOM/GRM observation
  26. EP241113a: Swift XRT weak detection
  27. GRB 241115B: Fermi GBM Final Real-time Localization
  28. EP241115a: EP detection of a fast X-ray transient
  29. EP241113a: No Detection in Fermi-GBM Observations
  30. GRB 241115A: Swift detection of a burst
  31. GRB 241115A: Fermi GBM Final Real-time Localization
  32. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  33. GRB 241113A: PRIME near-infrared upper limits
  34. GRB 241114A: Fermi GBM Final Real-time Localization
  35. GRB 241030A: LCO optical observation
  36. EP241113b/GRB 241113B: EP detection of GRB 241113B
  37. GRB 241113B: SVOM/GRM observation
  38. EP241113a: EP on-board trigger and autonomous follow-up observation
  39. GRB 241113A: Swift/UVOT Detection
  40. GRB 241113A: REM detection of the optical/NIR afterglow
  41. Konus-Wind detection of GRB 241107A (short/hard)
  42. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  43. GRB241113A: LCOGT (40-cm) optical counterpart detection
  44. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  45. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  46. GRB 241113A: Swift detection of a burst with an optical counterpart
  47. SVOM/GRM detection of a short burst from SGR 1E1841-045
  48. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  49. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  50. GRB 241112B: Swift-XRT afterglow detection
  51. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  52. GRB 241112B: SVOM/GRM observation
  53. GRB 241112B: SVOM/VT afterglow detection
  54. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  55. GRB 241112A: Fermi GBM Final Real-time Localization
  56. IPN triangulation of GRB 241107A (short/hard)
  57. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  58. GRB 241025C: VZLUSAT-2 detection
  59. GRB 241025A: VZLUSAT-2 detection
  60. GRB 241018A: cubesat Avion detection
  61. GRB 241111A: Fermi GBM Final Real-time Localization
  62. GRB 241030B: TESS detection of optical counterpart
  63. INTEGRAL detection of a burst from 1E 1841-045
  64. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  65. EP241109a: confirmation of a stellar flare by BOOTES-7
  66. EP241109a: EP on-board trigger and autonomous follow-up observation
  67. GRB 241030A: TESS observations
  68. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  69. GRB 241025A: radio detection with the VLA
  70. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  71. EP241107a: GSP detects optical counterpart
  72. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  73. GRB 241107A: SVOM/GRM detection of a short burst
  74. GRB 241105A: SVOM/GRM observation
  75. EP241107a: OHP/T193 photometric and spectroscopic observations
  76. GRB 241105a: PRIME near-infrared upper limits
  77. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  78. EP241107a: AKO Optical Afterglow Detection
  79. GRB241105A: Gemini-South Optical Afterglow Detection
  80. EP241107a: EP on-board trigger and autonomous follow-up observation
  81. GRB 241105A: Swift/UVOT Detection
  82. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  83. GRB 241105A: BOOTES-7 optical detection
  84. Konus-Wind detection of GRB 241105A (short with extended emission)
  85. Konus-Wind detection of GRB 241021A
  86. GRB 241105A: Swift-XRT afterglow detection
  87. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  88. GRB 240511A: LCO upper limits
  89. GRB 241104A: NOT optical non-detection
  90. GRB 241105A: Fermi GBM Final Real-time Localization
  91. GRB 241104A: SVOM/GRM observation
  92. EP241104a: EP detection of GRB 241104A X-ray emission
  93. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  94. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  95. GRB 241104A: Fermi GBM Final Real-time Localization
  96. GRB 241030A: GRBAlpha detection
  97. EP241101a: EP-FXT observations update
  98. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  99. EP241101a: Possible detection of an optical counterpart with FTW
  100. EP241103a: Swift XRT detection and improved X-ray position

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