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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"

5386 results found.

  1. GRB 241228A: Swift detection of a burst
  2. Fermi trigger No 756678579: Global MASTER-Net observations report
  3. EP241223a: Global MASTER-Net observations report
  4. Konus-Wind detection of GRB 241204A (short/hard)
  5. GRB 241217A/EP241217b: REM optical/NIR upper limits
  6. GRB 241218a: Liverpool Telescope optical follow-up
  7. EP241217a: Liverpool Telescope optical follow-up
  8. GRB 241218A: LCOGT Optical Upper Limit
  9. EP241217a: Global MASTER-Net observations report
  10. EP241217A: Non-detection from Fermi-GBM Observations
  11. GRB 241214A: GRBAlpha detection
  12. EP241217a: Gemini-North detection of the likely optical counterpart
  13. EP241217a: EP detection of an X-ray transient
  14. GRB 241213B: MAXI/GSC detection
  15. GRB 241213A: REM optical/NIR upper limits
  16. GRB 241212A : SVOM/VT bright optical afterglow
  17. Konus-Wind detection of GRB 241209B
  18. GRB 241209B: GRBAlpha detection
  19. GRB 241206C: GRBAlpha detection
  20. Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
  21. EP241208a: Global MASTER-Net observations report
  22. Fermi trigger No 755485387: Global MASTER-Net observations report
  23. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  24. Fermi GRB 241209C: Global MASTER-Net observations report
  25. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  26. Fermi GRB 241209A: Global MASTER-Net observations report
  27. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  28. Fermi GRB 241207B: Global MASTER-Net observations report
  29. Fermi GRB 241207A: Global MASTER-Net observations report
  30. GRB 241206C: SVOM/GRM observation of a likely short burst
  31. GRB 241204A: DDOTI Upper Limits on the Afterglow
  32. GRB 241204A: Fermi GBM Observation
  33. Fermi GRB 241204A: Global MASTER-Net observations report
  34. GRB 241204A: Fermi-LAT detection
  35. EP241202b: Kinder optical counterpart candidate
  36. EP241202b: Global MASTER-Net observations report
  37. EP241201a: Kinder optical counterpart candidate
  38. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  39. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  40. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  41. EP241126a: GSP detects optical counterpart
  42. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  43. Konus-Wind detection of GRB 241117A
  44. IPN triangulation of GRB 241117A
  45. GRB 241114B: Insight-HXMT/HE detection
  46. Fermi GRB 241118A: Global MASTER-Net observations report
  47. GRB 241117A: Fermi GBM Detection
  48. Fermi GRB 241117A: Global MASTER-Net observations report
  49. GRB 241117A: Fermi GBM Final Real-time Localization
  50. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  51. EP241113a: Swift XRT weak detection
  52. GRB 241113A: J-band observations with WINTER
  53. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  54. GRB 241113A: KAIT optical observations
  55. EP241113b: Global MASTER-Net observations report
  56. GRB 241113A: REM detection of the optical/NIR afterglow
  57. Fermi trigger No 753166198: Global MASTER-Net observations report
  58. GRB 241112B: AbAO optical upper limit
  59. IPN triangulation of GRB 241107A (short/hard)
  60. Fermi trigger No 752878030: Global MASTER-Net observations report
  61. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  62. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  63. EP241107a: AKO Optical Afterglow Follow-Up Observations
  64. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  65. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  66. EP241107a: AKO Optical Afterglow Detection
  67. EP241101a: CrAO ZTSH optical observations
  68. GRB 241030A: Mondy optical observations
  69. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  70. GRB 240511A: LCO upper limits
  71. Fermi GRB 241105A: Global MASTER-Net observations report
  72. EP241103a: GIT optical upper limit
  73. EP241021a: OHP/T193 further optical observations
  74. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  75. EP241103a: GOTO optical upper limit
  76. EP241103a: Swift XRT detection and improved X-ray position
  77. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  78. EP241103a: GSP optical upper limit
  79. EP241103A: LCO optical observations
  80. EP241103a: Global MASTER-Net observations report
  81. GRB 241030A: Rapid release of TESS data.
  82. GRB241030A: OHP/T193 optical observations
  83. Fermi trigger No 752083996: Global MASTER-Net observations report
  84. EP EP241030a: Global MASTER-Net observations report
  85. Fermi trigger No 752006065: Global MASTER-Net observations report
  86. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  87. GRB 241030B: AKO Optical Afterglow Detection
  88. GRB 241030B: Prompt enhanced Swift-XRT position
  89. GRB 241030A: Fermi-LAT detection
  90. GRB 241026A: LBT optical observations
  91. GRB 241030A: SVOM/VT optical afterglow observations
  92. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  93. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  94. GRB 241030A: Fermi GBM Final Real-time Localization
  95. EP241021a: SAO RAS observations of rebrightening
  96. GRB 241029A: GOTO optical afterglow detection
  97. EP 241026b: LBT possible optical counterpart (brightening source)
  98. EP EP241026b: Global MASTER-Net observations report
  99. Fermi GRB 241026A: Global MASTER-Net observations report
  100. GRB 241025A: COLIBRÍ Detection of the Afterglow

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