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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"

37582 results found.

  1. GRB 250722A: Fermi GBM Final Real-time Localization
  2. GRB 250713A : SVOM/ECLAIRs refined analysis
  3. GRB 250717B: SVOM/GRM observation
  4. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  5. GRB 250721A: Tiled Swift observations
  6. GRB 250721A: MAXI/GSC detection
  7. GRB 250721A: Fermi GBM Final Localization
  8. GRB 250720B: Fermi GBM Final Localization Correction
  9. GRB 250720A: Fermi GBM Final Localization
  10. Fermi trigger No 774730635: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  12. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  13. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  14. GRB 250717B: COLIBRÍ optical upper limit
  15. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  16. GRB 250717B: Swift-XRT observations
  17. GRB 250718B: Fermi GBM Final Localization Correction
  18. GRB 250718B: Fermi GBM Final Real-time Localization
  19. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  20. Swift Trigger 1334535: a possible GRB 250718A
  21. GRB 250717B: Swift ToO observations
  22. GRB 270713A: Kitab and AbAO Optical Observations
  23. GRB 250717B: Fermi GBM Observation
  24. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  25. Konus-Wind detection of GRB 250716A
  26. GRB 250716A: Swift-XRT afterglow detection
  27. GRB 250717B: Fermi GBM Final Real-time Localization
  28. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  29. GRB 250717A: Fermi GBM Final Real-time Localization
  30. GRB 250716A: Swift ToO observations
  31. GRB 250716A: GOTO tentative optical counterpart candidate
  32. GRB 250716A: Fermi GBM Observation
  33. GRB 250714A: SVOM/GRM observation
  34. Fermi GRB 250716A: Global MASTER-Net observations report
  35. GRB 250716A: Fermi GBM Final Real-time Localization
  36. Fermi GRB 250715A: Global MASTER-Net observations report
  37. GRB 250715A: Fermi GBM Final Real-time Localization
  38. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  39. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  40. GRB 250713A: Mephisto optical upper limits
  41. Fermi GRB 250714A: Global MASTER-Net observations report
  42. GRB 250713A: SVOM/VT optical upper limit
  43. GRB 250713A: NOT optical upper limits
  44. GRB 250713A: OHP/T193 upper limit
  45. GRB 250713A: SVOM/C-GFT upper limit
  46. GRB 250714A: Fermi GBM Final Real-time Localization
  47. GRB 250706B/C: 7DT Follow-up Observations
  48. GRB 250713A: Swift-XRT observations
  49. GRB 250713A: EP-FXT counterpart detection
  50. GRB 250706A: Swift-BAT refined analysis
  51. GRB 250702F: Swift-BAT refined analysis
  52. GRB 250628A: Swift-BAT refined analysis
  53. GRB 250713A: JinShan optical upper limits
  54. GRB 250713A: SVOM detection of a long burst
  55. GRB 250711A: DDOTI Optical Upper Limit
  56. GRB 250711A: SVOM/GRM observation
  57. Fermi GRB 250711A: Global MASTER-Net observations report
  58. GRB 250704A: GRANDMA observations
  59. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  60. GRB 250711A: Fermi GBM Final Real-time Localization
  61. GRB 250704A: SVOM/ECLAIRs refined analysis
  62. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  63. GRB 250704B / EP250704a: 1.3 GHz MeerKAT Detection
  64. GRB 250702B,D,E / EP250702a: ALMA detection
  65. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  66. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  67. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  68. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  69. GRB 250709A: Fermi GBM Final Localization
  70. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  71. GRB 250706B/C: Insight-HXMT detection
  72. EP250704a/GRB 250704B: 10 GHz VLA detection
  73. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  74. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  75. IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event
  76. GRB 250704B / EP250704a: VLA radio detection
  77. Fermi GRB 250708A: Global MASTER-Net observations report
  78. EP250704a/GRB250704B : HCT optical and NIR upper limits
  79. GRB 250708A: Fermi GBM Final Real-time Localization
  80. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  81. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  82. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  83. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  84. GRB 250702F: radio detection with the VLA
  85. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  86. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  87. GRB 250706B/C: Fermi-LAT detection
  88. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  89. GRB 250706B: Swift/UVOT Detection
  90. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  91. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  92. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  93. GRB 250702F: GRANDMA observations
  94. GRB 250706A: Swift-XRT refined Analysis
  95. GRB 250706B: refined SVOM/MXT data analysis
  96. GRB 250706A: Swift/UVOT Upper Limits
  97. GRB 250706B: REM optical observations
  98. GRB 250706A: REM optical/NIR observations
  99. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  100. Swift GRB 250706A: Global MASTER-Net observations report

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