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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"

41978 results found.

  1. GRB 250718B: Fermi GBM Final Localization Correction
  2. GRB 250718B: Fermi GBM Final Real-time Localization
  3. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  4. Swift Trigger 1334535: a possible GRB 250718A
  5. Swift GRB250718.01: Global MASTER-Net observations report
  6. GRB 250717B: Swift ToO observations
  7. GRB 270713A: Kitab and AbAO Optical Observations
  8. GRB 250717B: Fermi GBM Observation
  9. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  10. Konus-Wind detection of GRB 250716A
  11. GRB 250716A: Swift-XRT afterglow detection
  12. GRB 250717B: Fermi GBM Final Real-time Localization
  13. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  14. GRB 250717A: Fermi GBM Final Real-time Localization
  15. GRB 250716A: Swift ToO observations
  16. GRB 250716A: GOTO tentative optical counterpart candidate
  17. GRB 250716A: Fermi GBM Observation
  18. GRB 250714A: SVOM/GRM observation
  19. Fermi GRB 250716A: Global MASTER-Net observations report
  20. GRB 250716A: Fermi GBM Final Real-time Localization
  21. Fermi GRB 250715A: Global MASTER-Net observations report
  22. GRB 250715A: Fermi GBM Final Real-time Localization
  23. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  24. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  25. GRB 250713A: Mephisto optical upper limits
  26. Fermi GRB 250714A: Global MASTER-Net observations report
  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 250714A: Fermi GBM Final Real-time Localization
  32. GRB 250706B/C: 7DT Follow-up Observations
  33. GRB 250713A: Swift-XRT observations
  34. GRB 250713A: EP-FXT counterpart detection
  35. EP250711a: COLIBRÍ continuous optical observations
  36. GRB 250706A: Swift-BAT refined analysis
  37. GRB 250702F: Swift-BAT refined analysis
  38. GRB 250628A: Swift-BAT refined analysis
  39. LIGO/Virgo/KAGRA S250712cd: Updated Sky localization
  40. GRB 250713A: JinShan optical upper limits
  41. GRB 250713A: SVOM detection of a long burst
  42. EP250711a: Global MASTER-Net observations report
  43. GRB 250711A: DDOTI Optical Upper Limit
  44. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  45. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  46. GRB 250711A: SVOM/GRM observation
  47. EP250711a: NOT optical counterpart candidate
  48. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  49. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  50. Fermi GRB 250711A: Global MASTER-Net observations report
  51. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  52. GRB 250704A: GRANDMA observations
  53. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  54. GRB 250711A: Fermi GBM Final Real-time Localization
  55. GRB 250704A: SVOM/ECLAIRs refined analysis
  56. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  57. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  58. GRB 250704B / EP250704a: 1.3 GHz MeerKAT Detection
  59. GRB 250702B,D,E / EP250702a: ALMA detection
  60. IceCube-250708A: No Candidates from WINTER
  61. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  62. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  63. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  64. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  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. EP/WXT 01709181970: GOTO observations confirm stellar variability
  69. EP250704a/GRB 250704B: 10 GHz VLA detection
  70. The EP-WXT trigger 01709181970 is likely a flaring star
  71. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  72. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
  73. IceCube-250706A: No Candidates from WINTER
  74. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  75. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  76. IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event
  77. GRB 250704B / EP250704a: VLA radio detection
  78. Fermi GRB 250708A: Global MASTER-Net observations report
  79. IceCube-250708A: Global MASTER-Net observations report
  80. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  81. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  82. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  83. EP250704a/GRB250704B : HCT optical and NIR upper limits
  84. GRB 250708A: Fermi GBM Final Real-time Localization
  85. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  86. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  87. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  88. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  89. GRB 250702F: radio detection with the VLA
  90. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  91. IceCube-250706A: EP-FXT follow-up observations
  92. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  93. GRB 250706B/C: Fermi-LAT detection
  94. IceCube-250706A: Global MASTER-Net observations report
  95. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  96. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  97. GRB 250706B: Swift/UVOT Detection
  98. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  99. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  100. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst

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