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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"

28255 results found.

  1. SVOM J195836+32283 is not a real source
  2. EP250702a/GRB250702 B,D,E: uGMRT Radio detection in 1.26 GHz
  3. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  4. GRB 250721A: Fermi GBM Observation
  5. SVOM J195836+32283/sb25072103: NIR observations with WINTER
  6. GRB 250721A: Swift-XRT observations
  7. GRB 250717B: SVOM/GRM observation
  8. LIGO/Virgo/KAGRA S250711q: Updated Sky localization
  9. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  10. GRB 250721A: MAXI/GSC detection
  11. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  12. GRB 250717B: COLIBRÍ optical upper limit
  13. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  14. GRB 250717B: Swift-XRT observations
  15. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  16. Swift GRB250718.01: Global MASTER-Net observations report
  17. GRB 270713A: Kitab and AbAO Optical Observations
  18. GRB 250717B: Fermi GBM Observation
  19. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  20. GRB 250716A: Swift-XRT afterglow detection
  21. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  22. GRB 250716A: Fermi GBM Observation
  23. GRB 250714A: SVOM/GRM observation
  24. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  25. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  26. GRB 250713A: Mephisto optical upper limits
  27. GRB 250713A: SVOM/VT optical upper limit
  28. GRB 250713A: NOT optical upper limits
  29. GRB 250713A: OHP/T193 upper limit
  30. GRB 250713A: SVOM/C-GFT upper limit
  31. GRB 250706B/C: 7DT Follow-up Observations
  32. GRB 250713A: Swift-XRT observations
  33. GRB 250713A: EP-FXT counterpart detection
  34. EP250711a: COLIBRÍ continuous optical observations
  35. GRB 250706A: Swift-BAT refined analysis
  36. GRB 250702F: Swift-BAT refined analysis
  37. GRB 250628A: Swift-BAT refined analysis
  38. LIGO/Virgo/KAGRA S250712cd: Updated Sky localization
  39. GRB 250713A: JinShan optical upper limits
  40. GRB 250713A: SVOM detection of a long burst
  41. EP250711a: Global MASTER-Net observations report
  42. GRB 250711A: DDOTI Optical Upper Limit
  43. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  44. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  45. GRB 250711A: SVOM/GRM observation
  46. EP250711a: NOT optical counterpart candidate
  47. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  48. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  49. GRB 250704A: GRANDMA observations
  50. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  51. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  52. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  53. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  54. IceCube-250708A: No Candidates from WINTER
  55. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  56. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  57. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  58. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  59. EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6
  60. EP250704a/GRB 250704B: 10 GHz VLA detection
  61. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
  62. IceCube-250706A: No Candidates from WINTER
  63. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  64. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  65. LIGO/Virgo/KAGRA S250705cb: Updated Sky localization
  66. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  67. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  68. LIGO/Virgo/KAGRA S250701bq: Updated Sky localization
  69. EP250704a/GRB250704B : HCT optical and NIR upper limits
  70. LIGO/Virgo/KAGRA S250701bp: Updated Sky localization
  71. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  72. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  73. GRB 250702F: radio detection with the VLA
  74. IceCube-250706A: EP-FXT follow-up observations
  75. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  76. GRB 250706B/C: Fermi-LAT detection
  77. IceCube-250706A: Global MASTER-Net observations report
  78. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  79. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  80. GRB 250706B: Swift/UVOT Detection
  81. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  82. GRB 250702F: GRANDMA observations
  83. GRB 250706A: Swift-XRT refined Analysis
  84. GRB 250706B: refined SVOM/MXT data analysis
  85. GRB 250706A: Swift/UVOT Upper Limits
  86. GRB 250706B: REM optical observations
  87. GRB 250706A: REM optical/NIR observations
  88. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  89. IceCube-250416A: DDOTI Optical Upper Limit
  90. IceCube-250706A: COLIBRÍ optical upper limits
  91. GRB 250706A: JinShan optical upper limits
  92. GRB 250706A: SAO RAS optical observations
  93. EP250704A: NOWT Detection
  94. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  95. GRB250706B: Swift-XRT counterpart detection
  96. GRB 250706B: iTelescope optical observations
  97. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  98. GRB 250706B: SVOM/VT optical observation
  99. GRB 250706B: TRT bright optical counterpart detection
  100. GRB 250706A: GROWTH-India Telescope optical upper limit

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