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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"

37258 results found.

  1. Swift GRB 250725A: Global MASTER-Net OT detection
  2. GRB 250725A: Fermi GBM Final Real-time Localization
  3. Fermi GRB 250725A: Global MASTER-Net observations report
  4. Swift GRB 250725A: Global MASTER-Net observations report
  5. SVOM J195836+32283/sb25072103: Second VT observation
  6. GRB 250723B: Fermi GBM Final Real-time Localization
  7. GRB 250721A: Fermi GBM Observation
  8. GRB 250723A: Fermi GBM Final Real-time Localization
  9. Swift-BAT trigger 1334535 is not a GRB
  10. GRB 250721A: Swift-XRT observations
  11. GRB 250722A: Fermi GBM Final Real-time Localization
  12. GRB 250713A : SVOM/ECLAIRs refined analysis
  13. GRB 250717B: SVOM/GRM observation
  14. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  15. GRB 250721A: Tiled Swift observations
  16. GRB 250721A: MAXI/GSC detection
  17. GRB 250721A: Fermi GBM Final Localization
  18. GRB 250720B: Fermi GBM Final Localization Correction
  19. GRB 250720A: Fermi GBM Final Localization
  20. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  21. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  22. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  23. GRB 250717B: COLIBRÍ optical upper limit
  24. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  25. GRB 250717B: Swift-XRT observations
  26. GRB 250718B: Fermi GBM Final Localization Correction
  27. GRB 250718B: Fermi GBM Final Real-time Localization
  28. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  29. Swift Trigger 1334535: a possible GRB 250718A
  30. GRB 250717B: Swift ToO observations
  31. GRB 270713A: Kitab and AbAO Optical Observations
  32. GRB 250717B: Fermi GBM Observation
  33. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  34. Konus-Wind detection of GRB 250716A
  35. GRB 250716A: Swift-XRT afterglow detection
  36. GRB 250717B: Fermi GBM Final Real-time Localization
  37. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  38. GRB 250717A: Fermi GBM Final Real-time Localization
  39. GRB 250716A: Swift ToO observations
  40. GRB 250716A: GOTO tentative optical counterpart candidate
  41. GRB 250716A: Fermi GBM Observation
  42. GRB 250714A: SVOM/GRM observation
  43. Fermi GRB 250716A: Global MASTER-Net observations report
  44. GRB 250716A: Fermi GBM Final Real-time Localization
  45. Fermi GRB 250715A: Global MASTER-Net observations report
  46. GRB 250715A: Fermi GBM Final Real-time Localization
  47. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  48. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  49. GRB 250713A: Mephisto optical upper limits
  50. Fermi GRB 250714A: Global MASTER-Net observations report
  51. GRB 250713A: SVOM/VT optical upper limit
  52. GRB 250713A: NOT optical upper limits
  53. GRB 250713A: OHP/T193 upper limit
  54. GRB 250713A: SVOM/C-GFT upper limit
  55. GRB 250714A: Fermi GBM Final Real-time Localization
  56. GRB 250706B/C: 7DT Follow-up Observations
  57. GRB 250713A: Swift-XRT observations
  58. GRB 250713A: EP-FXT counterpart detection
  59. GRB 250706A: Swift-BAT refined analysis
  60. GRB 250702F: Swift-BAT refined analysis
  61. GRB 250628A: Swift-BAT refined analysis
  62. GRB 250713A: JinShan optical upper limits
  63. GRB 250713A: SVOM detection of a long burst
  64. GRB 250711A: DDOTI Optical Upper Limit
  65. GRB 250711A: SVOM/GRM observation
  66. Fermi GRB 250711A: Global MASTER-Net observations report
  67. GRB 250704A: GRANDMA observations
  68. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  69. GRB 250711A: Fermi GBM Final Real-time Localization
  70. GRB 250704A: SVOM/ECLAIRs refined analysis
  71. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  72. GRB 250704B / EP250704a: 1.3 GHz MeerKAT Detection
  73. GRB 250702B,D,E / EP250702a: ALMA detection
  74. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  75. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  76. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  77. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  78. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  79. GRB 250709A: Fermi GBM Final Localization
  80. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  81. GRB 250706B/C: Insight-HXMT detection
  82. EP250704a/GRB 250704B: 10 GHz VLA detection
  83. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  84. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  85. GRB 250704B / EP250704a: VLA radio detection
  86. Fermi GRB 250708A: Global MASTER-Net observations report
  87. EP250704a/GRB250704B : HCT optical and NIR upper limits
  88. GRB 250708A: Fermi GBM Final Real-time Localization
  89. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  90. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  91. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  92. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  93. GRB 250702F: radio detection with the VLA
  94. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  95. IceCube-250706A: EP-FXT follow-up observations
  96. GRB 250706B/C: Fermi-LAT detection
  97. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  98. GRB 250706B: Swift/UVOT Detection
  99. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  100. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B

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