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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').
  1. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  2. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  3. GRB 241112B: Mephisto optical upper limits
  4. GRB 241112B: GOTO optical upper limits
  5. GRB 241112B: Swift ToO observations
  6. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  7. GRB 241107A: INTEGRAL IBIS localization
  8. EP241107a: EP-FXT follow-up observations
  9. GRB 241112A: Fermi GBM Final Real-time Localization
  10. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  11. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  12. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  13. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  14. IPN triangulation of GRB 241107A (short/hard)
  15. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  16. GRB 241025C: VZLUSAT-2 detection
  17. GRB 241025A: VZLUSAT-2 detection
  18. GRB 241018A: cubesat Avion detection
  19. Fermi trigger No 752990530: Global MASTER-Net observations report
  20. GRB 241111A: Fermi GBM Final Real-time Localization
  21. GRB 241030B: TESS detection of optical counterpart
  22. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  23. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  24. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  25. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  26. Fermi trigger No 752878030: Global MASTER-Net observations report
  27. Integral GRB241109.89: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  29. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  30. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  31. INTEGRAL detection of a burst from 1E 1841-045
  32. EP241107a: AbAO optical upper limit
  33. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  34. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  35. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  36. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  37. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  38. EP241109a: confirmation of a stellar flare by BOOTES-7
  39. EP241109a: EP on-board trigger and autonomous follow-up observation
  40. GRB 241108A: Swift-XRT observations
  41. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  42. EP241107A: MASTER optical observations of xray transient
  43. EP241107a: KAIT optical observations
  44. GRB 241108A: Swift ToO observations
  45. GRB 241030A: TESS observations
  46. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  47. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  48. EP241107a: Kinder optical follow-up observations
  49. GRB 241025A: radio detection with the VLA
  50. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  51. EP241107a: AKO Optical Afterglow Follow-Up Observations
  52. EP241107a: GSP detects optical counterpart
  53. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  54. GRB 241107A: SVOM/GRM detection of a short burst
  55. GRB 241105A: EP-FXT follow-up observations
  56. GRB 241105A: SVOM/GRM observation
  57. EP241107a: OHP/T193 photometric and spectroscopic observations
  58. GRB 241105a: PRIME near-infrared upper limits
  59. EP241107a: FTW Optical and NIR observations of the optical counterpart
  60. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  61. EP241107a: GIT optical observations
  62. EP241107a: Global MASTER-Net observations report
  63. EP241107a: SVOM/C-GFT optical observations
  64. EP241107a: AKO Optical Afterglow Detection
  65. GRB 241025A: LBT optical observations
  66. GRB241105A: Gemini-South Optical Afterglow Detection
  67. EP241107a: EP on-board trigger and autonomous follow-up observation
  68. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  69. GRB 241105A: Swift/UVOT Detection
  70. EP241101a: CrAO ZTSH optical observations
  71. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  72. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  73. GRB 241105A: BOOTES-7 optical detection
  74. GRB 241030A: Mondy optical observations
  75. GRB241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  76. Konus-Wind detection of GRB 241105A (short with extended emission)
  77. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  78. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  79. Konus-Wind detection of GRB 241021A
  80. GRB 241105A: SVOM/VT optical afterglow observations
  81. GRB 241105A: Swift-XRT afterglow detection
  82. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  83. GRB 241104A: Swift-XRT observations
  84. GRB 240511A: LCO upper limits
  85. GRB241104A: Fermi GBM Observation
  86. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  87. GRB 241105A: Swift ToO observations
  88. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  89. GRB 241104A: Swift ToO observations
  90. GRB 241104A: NOT optical non-detection
  91. GRB 241105A: GOTO tentative optical counterpart candidate
  92. Fermi GRB 241105A: Global MASTER-Net observations report
  93. GRB 241104A: SVOM/VT optical candidate
  94. GRB 241105A: Fermi GBM Final Real-time Localization
  95. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  96. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  97. GRB 241104A: SVOM/GRM observation
  98. EP241104a: EP detection of GRB 241104A X-ray emission
  99. GRB 241010A: host galaxy redshift z = 0.977
  100. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02

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