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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"

32717 results found.

  1. GRB 250717B: SVOM/GRM observation
  2. LIGO/Virgo/KAGRA S250711q: Updated Sky localization
  3. GRB 250721A: Tiled Swift observations
  4. GRB 250721A: MAXI/GSC detection
  5. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  6. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  7. GRB 250717B: COLIBRÍ optical upper limit
  8. GRB 250718B: Fermi GBM Final Localization Correction
  9. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  10. GRB 250717B: Swift ToO observations
  11. GRB 270713A: Kitab and AbAO Optical Observations
  12. GRB 250717B: Fermi GBM Observation
  13. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  14. Konus-Wind detection of GRB 250716A
  15. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  16. GRB 250716A: Swift ToO observations
  17. GRB 250714A: SVOM/GRM observation
  18. Fermi GRB 250716A: Global MASTER-Net observations report
  19. Fermi GRB 250715A: Global MASTER-Net observations report
  20. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  21. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  22. GRB 250713A: Mephisto optical upper limits
  23. Fermi GRB 250714A: Global MASTER-Net observations report
  24. GRB 250713A: SVOM/VT optical upper limit
  25. GRB 250713A: NOT optical upper limits
  26. GRB 250713A: OHP/T193 upper limit
  27. GRB 250713A: SVOM/C-GFT upper limit
  28. GRB 250706B/C: 7DT Follow-up Observations
  29. GRB 250713A: EP-FXT counterpart detection
  30. EP250711a: COLIBRÍ continuous optical observations
  31. GRB 250706A: Swift-BAT refined analysis
  32. GRB 250702F: Swift-BAT refined analysis
  33. GRB 250628A: Swift-BAT refined analysis
  34. LIGO/Virgo/KAGRA S250712cd: Updated Sky localization
  35. GRB 250713A: JinShan optical upper limits
  36. EP250711a: Global MASTER-Net observations report
  37. GRB 250711A: DDOTI Optical Upper Limit
  38. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  39. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate (duplicate submission)
  40. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  41. GRB 250711A: SVOM/GRM observation
  42. EP250711a: NOT optical counterpart candidate
  43. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  44. Fermi GRB 250711A: Global MASTER-Net observations report
  45. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  46. GRB 250704A: GRANDMA observations
  47. GRB 250704A: SVOM/ECLAIRs refined analysis
  48. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  49. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  50. GRB 250704B / EP250704a: 1.3 GHz MeerKAT Detection
  51. GRB 250702B,D,E / EP250702a: ALMA detection
  52. IceCube-250708A: No Candidates from WINTER
  53. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  54. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  55. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  56. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  57. GRB 250706B/C: Insight-HXMT detection
  58. EP/WXT 01709181970: GOTO observations confirm stellar variability
  59. EP250704a/GRB 250704B: 10 GHz VLA detection
  60. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  61. IceCube-250706A: No Candidates from WINTER
  62. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  63. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  64. GRB 250704B / EP250704a: VLA radio detection
  65. Fermi GRB 250708A: Global MASTER-Net observations report
  66. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  67. LIGO/Virgo/KAGRA S250705cb: Updated Sky localization
  68. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  69. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  70. LIGO/Virgo/KAGRA S250701bq: Updated Sky localization
  71. EP250704a/GRB250704B : HCT optical and NIR upper limits
  72. LIGO/Virgo/KAGRA S250701bp: Updated Sky localization
  73. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  74. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  75. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  76. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  77. GRB 250702F: radio detection with the VLA
  78. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  79. IceCube-250706A: EP-FXT follow-up observations
  80. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  81. GRB 250706B/C: Fermi-LAT detection
  82. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  83. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  84. GRB 250706B: Swift/UVOT Detection
  85. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  86. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  87. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  88. GRB 250702F: GRANDMA observations
  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. IceCube-250416A: DDOTI Optical Upper Limit
  95. IceCube-250706A: COLIBRÍ optical upper limits
  96. Swift GRB 250706A: Global MASTER-Net observations report
  97. GRB 250706A: JinShan optical upper limits
  98. GRB 250706A: SAO RAS optical observations
  99. EP250704A: NOWT Detection
  100. GRB 250706A: SVOM/C-GFT upper limit in eary phase

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