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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"

37945 results found.

  1. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  2. GRB 250721A: Tiled Swift observations
  3. GRB 250721A: MAXI/GSC detection
  4. GRB 250721A: Fermi GBM Final Localization
  5. GRB 250720B: Fermi GBM Final Localization Correction
  6. GRB 250720A: Fermi GBM Final Localization
  7. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  8. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  9. GRB 250717B: COLIBRÍ optical upper limit
  10. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  11. GRB 250717B: Swift-XRT observations
  12. GRB 250718B: Fermi GBM Final Localization Correction
  13. GRB 250718B: Fermi GBM Final Real-time Localization
  14. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  15. Swift Trigger 1334535: a possible GRB 250718A
  16. Swift GRB250718.01: Global MASTER-Net observations report
  17. GRB 250717B: Swift ToO observations
  18. GRB 270713A: Kitab and AbAO Optical Observations
  19. GRB 250717B: Fermi GBM Observation
  20. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  21. Konus-Wind detection of GRB 250716A
  22. GRB 250716A: Swift-XRT afterglow detection
  23. GRB 250717B: Fermi GBM Final Real-time Localization
  24. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  25. GRB 250717A: Fermi GBM Final Real-time Localization
  26. GRB 250716A: Swift ToO observations
  27. GRB 250716A: GOTO tentative optical counterpart candidate
  28. GRB 250716A: Fermi GBM Observation
  29. GRB 250714A: SVOM/GRM observation
  30. Fermi GRB 250716A: Global MASTER-Net observations report
  31. GRB 250716A: Fermi GBM Final Real-time Localization
  32. Fermi GRB 250715A: Global MASTER-Net observations report
  33. GRB 250715A: Fermi GBM Final Real-time Localization
  34. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  35. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  36. GRB 250713A: Mephisto optical upper limits
  37. Fermi GRB 250714A: Global MASTER-Net observations report
  38. GRB 250713A: SVOM/VT optical upper limit
  39. GRB 250713A: NOT optical upper limits
  40. GRB 250713A: OHP/T193 upper limit
  41. GRB 250713A: SVOM/C-GFT upper limit
  42. GRB 250714A: Fermi GBM Final Real-time Localization
  43. GRB 250706B/C: 7DT Follow-up Observations
  44. GRB 250713A: Swift-XRT observations
  45. GRB 250713A: EP-FXT counterpart detection
  46. GRB 250706A: Swift-BAT refined analysis
  47. GRB 250702F: Swift-BAT refined analysis
  48. GRB 250628A: Swift-BAT refined analysis
  49. GRB 250713A: JinShan optical upper limits
  50. GRB 250713A: SVOM detection of a long burst
  51. GRB 250711A: DDOTI Optical Upper Limit
  52. GRB 250711A: SVOM/GRM observation
  53. Fermi GRB 250711A: Global MASTER-Net observations report
  54. GRB 250704A: GRANDMA observations
  55. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  56. GRB 250711A: Fermi GBM Final Real-time Localization
  57. GRB 250704A: SVOM/ECLAIRs refined analysis
  58. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  59. GRB 250704B / EP250704a: 1.3 GHz MeerKAT Detection
  60. GRB 250702B,D,E / EP250702a: ALMA detection
  61. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  62. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  63. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  64. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  65. GRB 250709A: Fermi GBM Final Localization
  66. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  67. GRB 250706B/C: Insight-HXMT detection
  68. EP250704a/GRB 250704B: 10 GHz VLA detection
  69. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  70. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  71. GRB 250704B / EP250704a: VLA radio detection
  72. Fermi GRB 250708A: Global MASTER-Net observations report
  73. EP250704a/GRB250704B : HCT optical and NIR upper limits
  74. GRB 250708A: Fermi GBM Final Real-time Localization
  75. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  76. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  77. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  78. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  79. GRB 250702F: radio detection with the VLA
  80. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  81. GRB 250706B/C: Fermi-LAT detection
  82. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  83. GRB 250706B: Swift/UVOT Detection
  84. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  85. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  86. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  87. GRB 250702F: GRANDMA observations
  88. GRB 250706A: Swift-XRT refined Analysis
  89. GRB 250706B: refined SVOM/MXT data analysis
  90. GRB 250706A: Swift/UVOT Upper Limits
  91. GRB 250706B: REM optical observations
  92. GRB 250706A: REM optical/NIR observations
  93. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  94. Swift GRB 250706A: Global MASTER-Net observations report
  95. GRB 250706A: JinShan optical upper limits
  96. GRB 250706A: SAO RAS optical observations
  97. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  98. GRB250706B: Swift-XRT counterpart detection
  99. GRB 250706B: iTelescope optical observations
  100. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart

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