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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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').
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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"

32502 results found.

  1. Konus-Wind detection of GRB 250116A
  2. GRB 250116A: GECAM-B detection of a long burst
  3. GRB 241217A / EP241217B: radio detection with the VLA
  4. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  5. GRB 250116A: Fermi-LAT detection
  6. GRB 250114B: Swift-XRT afterglow detection
  7. GRB 250114B: SVOM/VT upper limit
  8. EP250108a: MeerKAT radio upper limit
  9. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  10. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  11. Konus-Wind detection of GRB 250113A
  12. IPN triangulation of GRB 250113A
  13. GRB 250114B: Liverpool Telescope optical upper limit
  14. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  15. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  16. GRB 250114A: LCO optical counterpart detection.
  17. GRB 250114B: OHP/T193 optical upper limit
  18. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  19. GRB 250114A: LCOGT optical afterglow i-band detection
  20. GRB 250114B : GIT optical upper limit
  21. GRB 250114B: Swift ToO observations
  22. EP250111a: SAO RAS optical upper limit
  23. EP250108a: correction to GCN 38908
  24. GRB 250113A: INTEGRAL/SPI-ACS detection
  25. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  26. GRB 250114A: REM detection of the optical and NIR counterpart
  27. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  28. GRB 250114A: LCO optical observations
  29. GRB 250114A: TRT optical observations
  30. Swift GRB 250114A: Global MASTER-Net observations report
  31. GRB 250101A: Terskol Zeiss-2000 optical observations
  32. EP250108a / AT 2025kg: SAO RAS optical observations
  33. EP241021a: SMA radio observation
  34. GRB 250107A: VZLUSAT-2 detection
  35. GRB 250109A / EP250109a: GRBAlpha detection
  36. GRB 250107D: GRBAlpha detection
  37. EP250111a: KAIT optical observations
  38. GRB 250109A / EP250109a: Mephisto optical upper limits
  39. EP250108a: Mephisto detection
  40. EP250111a: Mondy optical observation
  41. EP250108a / AT 2025kg: LCO optical observations
  42. EP250111a: Global MASTER-Net observations report
  43. EP250111a: Swift/XRT detection and fading
  44. EP250108a / AT 2025kg: Swift UVOT detections
  45. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  46. EP250108a: optical follow-up observations with the Liverpool Telescope
  47. EP250111a: NOT likely optical counterpart
  48. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  49. GRB 250101B: Fermi GBM Observation
  50. EP250108a: further NOT optical observations
  51. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  52. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  53. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  54. GRB 250108A: Swift/XRT afterglow fading
  55. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  56. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  57. Konus-Wind detection of GRB 250107C
  58. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  59. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  60. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  61. GRB 250101A: CMO RC-500 optical observations
  62. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  63. EP250108a: EP-FXT follow-up observation
  64. GRB 250109A: Fermi GBM Observation
  65. EP250108a: NOT optical observations
  66. GRB 250109a: GMG Optical Upper Limit
  67. EP250109a: Swift/UVOT non-detection
  68. Konus-Wind detection of GRB 250107D (short/hard)
  69. IPN triangulation of GRB 250107D (short/hard)
  70. IPN triangulation of GRB 250107C
  71. EP250108a: Liverpool Telescope likely optical counterpart
  72. GRB 250108B: Gemini-North likely redshift z = 2.197
  73. GRB 250108B: Swift-BAT refined analysis
  74. GRB 250108B: 1.3m DFOT upper limit
  75. GRB 250108B: REM optical/NIR upper limits
  76. GRB 250109A /EP250109a: Fermi GBM Final Localization
  77. EP250109a: SVOM/VT optical candidate
  78. EP250109a: Global MASTER-Net observations report
  79. GRB 250101A: Terskol K-800 optical observations
  80. EP250109a: GOTO optical upper limits
  81. EP250109a: Swift/XRT non-detection
  82. GRB 250108A: Swift/UVOT Upper Limits
  83. EP250108a: Global MASTER-Net observations report
  84. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  85. GRB 250108A: NOT optical upper limit
  86. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  87. Swift GRB 250108B: Global MASTER-Net observations report
  88. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  89. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  90. GRB 250103A: 1.6m Mephisto optical observations
  91. GRB 250108A:SVOM/VT optical candidate
  92. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  93. GRB 250108B: Swift/UVOT Upper Limits
  94. GRB 250108A: Swift ToO observations
  95. GRB 250107A: Fermi GBM Observation
  96. GRB 241228B: Fermi-LAT detection
  97. Fermi GRB 250107B: Global MASTER-Net observations report
  98. GRB 250107A: Swift ToO observations
  99. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  100. GRB 250106A: SVOM/VT 2nd optical deep observation

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