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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32570 results found.

  1. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  2. EP250711a: CrAO and Assy optical observations
  3. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  4. EP250730a: Global MASTER-Net observations report
  5. EP250730a: COLIBRÍ optical upper limit
  6. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  7. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  8. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  9. GRB 250725A: AstroSat CZTI detection
  10. GRB 250727A: EP-FXT follow-up observation
  11. GRB 250725A: PRIME near-infrared observations
  12. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  13. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  14. GRB: Clarification on Gamma-Ray Burst Naming Convention
  15. GRB 250727A: SVOM/ECLAIRs refined analysis
  16. EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
  17. GRB 250728A: COLIBRÍ optical upper limit
  18. GRB 250728A: Fermi GBM Observation
  19. LIGO/Virgo/KAGRA S250727dc: Updated Sky localization
  20. GRB 250728A: Swift ToO observations
  21. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  22. GRB 250727A: AST3-2 Upper limit
  23. LIGO/Virgo/KAGRA S250727cl: Updated Sky localization
  24. GRB 250727A: EP-FXT counterpart detection
  25. GRB250727A: SVOM/VT optical upper limit
  26. LIGO/Virgo/KAGRA S250727dc: Identification of a GW compact binary merger candidate
  27. LIGO/Virgo/KAGRA S250727cl: Identification of a GW compact binary merger candidate
  28. LIGO/Virgo/KAGRA S250725j: DECam GW-MMADS candidates
  29. LIGO/Virgo/KAGRA S250725l: Updated Sky localization
  30. LIGO/Virgo/KAGRA S250726ak: Updated Sky localization
  31. LIGO/Virgo/KAGRA S250726ak: Identification of a GW compact binary merger candidate
  32. GRB 250725A: Fermi GBM Observation
  33. LIGO/Virgo/KAGRA S250725j: Updated Sky localization
  34. GRB 250725A: Swift-BAT refined analysis
  35. Konus-Wind detection of GRB 250725A
  36. GRB 250725A: SVOM/GRM observation
  37. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  38. GRB 250725A: Swift/UVOT Upper Limits
  39. GRB 250725A: Fermi-LAT detection
  40. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  41. GRB 250725A: BOOTES-7 early optical detection
  42. GRB 250725A: SVOM/VT optical candidate
  43. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate (duplicate submission)
  44. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate
  45. LIGO/Virgo/KAGRA S250725j: Identification of a GW compact binary merger candidate
  46. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  47. SVOM J195836+32283 is not a real source
  48. SVOM J195836+32283/sb25072103: Second VT observation
  49. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  50. GRB 250721A: Fermi GBM Observation
  51. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  52. SVOM J195836+32283/sb25072103: NIR observations with WINTER
  53. GRB 250713A : SVOM/ECLAIRs refined analysis
  54. GRB 250717B: SVOM/GRM observation
  55. LIGO/Virgo/KAGRA S250711q: Updated Sky localization
  56. GRB 250721A: Tiled Swift observations
  57. GRB 250721A: MAXI/GSC detection
  58. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  59. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  60. GRB 250717B: COLIBRÍ optical upper limit
  61. GRB 250718B: Fermi GBM Final Localization Correction
  62. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  63. GRB 250717B: Swift ToO observations
  64. GRB 270713A: Kitab and AbAO Optical Observations
  65. GRB 250717B: Fermi GBM Observation
  66. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  67. Konus-Wind detection of GRB 250716A
  68. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  69. GRB 250716A: Swift ToO observations
  70. GRB 250714A: SVOM/GRM observation
  71. Fermi GRB 250716A: Global MASTER-Net observations report
  72. Fermi GRB 250715A: Global MASTER-Net observations report
  73. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  74. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  75. GRB 250713A: Mephisto optical upper limits
  76. Fermi GRB 250714A: Global MASTER-Net observations report
  77. GRB 250713A: SVOM/VT optical upper limit
  78. GRB 250713A: NOT optical upper limits
  79. GRB 250713A: OHP/T193 upper limit
  80. GRB 250713A: SVOM/C-GFT upper limit
  81. GRB 250706B/C: 7DT Follow-up Observations
  82. GRB 250713A: EP-FXT counterpart detection
  83. EP250711a: COLIBRÍ continuous optical observations
  84. GRB 250706A: Swift-BAT refined analysis
  85. GRB 250702F: Swift-BAT refined analysis
  86. GRB 250628A: Swift-BAT refined analysis
  87. LIGO/Virgo/KAGRA S250712cd: Updated Sky localization
  88. GRB 250713A: JinShan optical upper limits
  89. EP250711a: Global MASTER-Net observations report
  90. GRB 250711A: DDOTI Optical Upper Limit
  91. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  92. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate (duplicate submission)
  93. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  94. GRB 250711A: SVOM/GRM observation
  95. EP250711a: NOT optical counterpart candidate
  96. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  97. Fermi GRB 250711A: Global MASTER-Net observations report
  98. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  99. GRB 250704A: GRANDMA observations
  100. GRB 250704A: SVOM/ECLAIRs refined analysis

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