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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. EP241113b: Global MASTER-Net observations report
  2. EP241113b/GRB 241113B: EP detection of GRB 241113B
  3. Fermi-LAT gamma-ray observations of IceCube-241113A
  4. GRB 241113B: SVOM/GRM observation
  5. EP241113a: EP on-board trigger and autonomous follow-up observation
  6. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  7. GRB 241113A: Swift-XRT refined Analysis
  8. EP241107a: SOAR upper limits
  9. GRB 241113A: Swift/UVOT Detection
  10. GRB 241113A: REM detection of the optical/NIR afterglow
  11. Konus-Wind detection of GRB 241107A (short/hard)
  12. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  13. Fermi Gamma-ray Burst Monitor trigger 753166198/241113201 is not a GRB
  14. GRB 241113B: Swift ToO observations
  15. GRB 241113A: LCO optical observations
  16. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  17. GRB 241112B: GMG Optical Upper Limit
  18. GRB 241113A: Enhanced Swift-XRT position
  19. GRB241113A: LCOGT (40-cm) optical counterpart detection
  20. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  21. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  22. GRB 241113A: Swift detection of a burst with an optical counterpart
  23. Swift GRB241113.33: Global MASTER-Net observations report
  24. SVOM/GRM detection of a short burst from SGR 1E1841-045
  25. Fermi trigger No 753166198: Global MASTER-Net observations report
  26. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  27. GRB 241105A: ATCA Radio Upper Limits
  28. GRB 241112B: AbAO optical upper limit
  29. GRB 241107A: GROWTH-India telescope optical upper limit
  30. IceCube Alert 241113.02: Global MASTER-Net observations report
  31. Fermi GRB 241112A: Global MASTER-Net observations report
  32. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  33. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  34. GRB 241112B: Swift-XRT afterglow detection
  35. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  36. GRB 241112B: SVOM/GRM observation
  37. GRB 241112B: SVOM/VT afterglow detection
  38. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  39. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  40. GRB 241112B: Mephisto optical upper limits
  41. GRB 241112B: GOTO optical upper limits
  42. GRB 241112B: Swift ToO observations
  43. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  44. GRB 241107A: INTEGRAL IBIS localization
  45. EP241107a: EP-FXT follow-up observations
  46. GRB 241112A: Fermi GBM Final Real-time Localization
  47. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  48. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  49. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  50. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  51. IPN triangulation of GRB 241107A (short/hard)
  52. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  53. GRB 241025C: VZLUSAT-2 detection
  54. GRB 241025A: VZLUSAT-2 detection
  55. GRB 241018A: cubesat Avion detection
  56. Fermi trigger No 752990530: Global MASTER-Net observations report
  57. GRB 241111A: Fermi GBM Final Real-time Localization
  58. GRB 241030B: TESS detection of optical counterpart
  59. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  60. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  61. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  62. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  63. Fermi trigger No 752878030: Global MASTER-Net observations report
  64. Integral GRB241109.89: Global MASTER-Net observations report
  65. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  66. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  67. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  68. INTEGRAL detection of a burst from 1E 1841-045
  69. EP241107a: AbAO optical upper limit
  70. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  71. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  72. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  73. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  75. EP241109a: confirmation of a stellar flare by BOOTES-7
  76. EP241109a: EP on-board trigger and autonomous follow-up observation
  77. GRB 241108A: Swift-XRT observations
  78. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  79. EP241107A: MASTER optical observations of xray transient
  80. EP241107a: KAIT optical observations
  81. GRB 241108A: Swift ToO observations
  82. GRB 241030A: TESS observations
  83. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  84. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  85. EP241107a: Kinder optical follow-up observations
  86. GRB 241025A: radio detection with the VLA
  87. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  88. EP241107a: AKO Optical Afterglow Follow-Up Observations
  89. EP241107a: GSP detects optical counterpart
  90. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  91. GRB 241107A: SVOM/GRM detection of a short burst
  92. GRB 241105A: EP-FXT follow-up observations
  93. GRB 241105A: SVOM/GRM observation
  94. EP241107a: OHP/T193 photometric and spectroscopic observations
  95. GRB 241105a: PRIME near-infrared upper limits
  96. EP241107a: FTW Optical and NIR observations of the optical counterpart
  97. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  98. EP241107a: GIT optical observations
  99. EP241107a: Global MASTER-Net observations report
  100. EP241107a: SVOM/C-GFT optical observations

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