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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

37291 results found.

  1. GRB 250119C: Fermi GBM Observation
  2. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  3. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  4. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  5. EP250108a: AbAO, CMO and Terskol optical upper limits
  6. Konus-Wind detection of GRB 250118B
  7. GRB 250121A: Fermi GBM Observation
  8. IPN triangulation of GRB 250118B
  9. Konus-Wind detection of GRB 250119B
  10. IPN triangulation of GRB 250119B
  11. GRB 250122A: Fermi GBM Final Real-time Localization
  12. Improved IPN triangulation of GRB 250107C
  13. GRB 250114A: Swift-BAT refined analysis
  14. GRB 250121A: INTEGRAL/SPI-ACS detection
  15. GRB 250121A: Fermi-LAT detection
  16. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  17. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  18. GRB 250121A: Fermi GBM Final Real-time Localization
  19. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  20. GRB 250119B: Fermi GBM Observation
  21. Konus-Wind detection of GRB 250117A
  22. IPN triangulation of GRB 250117A (short)
  23. ATCA detection of possible radio counterpart to GRB 250114A
  24. GRB 250119B: INTEGRAL/SPI-ACS detection
  25. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  26. EP 250108A: Late-time optical observation by LCO
  27. GRB 250117A: SVOM/GRM observation of a short burst
  28. GRB 250119C: Fermi GBM Final Real-time Localization
  29. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  30. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  31. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  32. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  33. GRB 250117A: GECAM observation of a short burst
  34. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  35. GRB 250119B: Fermi GBM Final Real-time Localization
  36. GRB 250119A: Fermi GBM Final Real-time Localization
  37. GRB 250118A: Fermi GBM Final Real-time Localization
  38. EP250108a / AT2025kg: VLA radio upper limit
  39. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  40. Konus-Wind detection of GRB 250116A
  41. GRB 250116A: GECAM-B detection of a long burst
  42. GRB 241217A / EP241217B: radio detection with the VLA
  43. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  44. Swift Trigger 1282245 is not a GRB
  45. GRB 250116A: Fermi-LAT detection
  46. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  47. GRB 250114B: Swift-XRT afterglow detection
  48. GRB 250114B: SVOM/VT upper limit
  49. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  50. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  51. Konus-Wind detection of GRB 250113A
  52. IPN triangulation of GRB 250113A
  53. GRB 250114B: Liverpool Telescope optical upper limit
  54. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  55. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  56. GRB 250114B: Swift-XRT observations
  57. GRB 250114A: LCO optical counterpart detection.
  58. GRB 250114B: OHP/T193 optical upper limit
  59. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  60. GRB 250114A: Swift-XRT refined Analysis
  61. GRB 250114A: LCOGT optical afterglow i-band detection
  62. GRB 250114B : GIT optical upper limit
  63. GRB 250114B: Swift ToO observations
  64. EP250111a: SAO RAS optical upper limit
  65. GRB 250114B: a short GRB detected with INTEGRAL
  66. GRB 250114A: Enhanced Swift-XRT position
  67. GRB 250113A: INTEGRAL/SPI-ACS detection
  68. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  69. GRB 250114A: REM detection of the optical and NIR counterpart
  70. Swift GRB250114A: Global MASTER-Net OT detection
  71. GRB 250114A: LCO optical observations
  72. GRB 250114A: TRT optical observations
  73. Swift GRB 250114A: Global MASTER-Net observations report
  74. GRB 250114A: Swift detection of a burst with an optical counterpart
  75. GRB 250101A: Terskol Zeiss-2000 optical observations
  76. EP250108a / AT 2025kg: SAO RAS optical observations
  77. GRB 250113A: SVOM/GRM observation of a long burst
  78. GRB 250107A: VZLUSAT-2 detection
  79. GRB 250109A / EP250109a: GRBAlpha detection
  80. GRB 250107D: GRBAlpha detection
  81. GRB 250106A: Swift-XRT afterglow detection
  82. EP250111a: KAIT optical observations
  83. GRB 250109A / EP250109a: Mephisto optical upper limits
  84. EP250108a: Mephisto detection
  85. EP250111a: Mondy optical observation
  86. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  87. GRB 250101B: Fermi GBM Observation
  88. EP250108a: further NOT optical observations
  89. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  90. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  91. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  92. GRB 250108A: Swift/XRT afterglow fading
  93. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  94. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  95. Konus-Wind detection of GRB 250107C
  96. GRB 250101A: CMO RC-500 optical observations
  97. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  98. GRB 250109A: Fermi GBM Observation
  99. EP250108a: NOT optical observations
  100. GRB 250109a: GMG Optical Upper Limit

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