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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').
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"

32191 results found.

  1. GRB 250114A: LCO optical counterpart detection.
  2. GRB 250114B: OHP/T193 optical upper limit
  3. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  4. GRB 250114A: Swift-XRT refined Analysis
  5. GRB 250114A: LCOGT optical afterglow i-band detection
  6. GRB 250114B : GIT optical upper limit
  7. GRB 250114B: Swift ToO observations
  8. EP250111a: SAO RAS optical upper limit
  9. GRB 250114B: a short GRB detected with INTEGRAL
  10. GRB 250114A: Enhanced Swift-XRT position
  11. GRB 250113A: INTEGRAL/SPI-ACS detection
  12. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  13. GRB 250114A: REM detection of the optical and NIR counterpart
  14. GRB 250114A: LCO optical observations
  15. GRB 250114A: TRT optical observations
  16. Swift GRB 250114A: Global MASTER-Net observations report
  17. GRB 250114A: Swift detection of a burst with an optical counterpart
  18. GRB 250101A: Terskol Zeiss-2000 optical observations
  19. EP250108a / AT 2025kg: SAO RAS optical observations
  20. GRB 250113A: SVOM/GRM observation of a long burst
  21. GRB 250107A: VZLUSAT-2 detection
  22. GRB 250109A / EP250109a: GRBAlpha detection
  23. GRB 250107D: GRBAlpha detection
  24. GRB 250106A: Swift-XRT afterglow detection
  25. EP250111a: KAIT optical observations
  26. GRB 250109A / EP250109a: Mephisto optical upper limits
  27. EP250111a: Mondy optical observation
  28. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  29. GRB 250101B: Fermi GBM Observation
  30. EP250108a: further NOT optical observations
  31. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  32. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  33. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  34. GRB 250108A: Swift/XRT afterglow fading
  35. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  36. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  37. Konus-Wind detection of GRB 250107C
  38. GRB 250101A: CMO RC-500 optical observations
  39. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  40. GRB 250109A: Fermi GBM Observation
  41. EP250108a: NOT optical observations
  42. GRB 250109a: GMG Optical Upper Limit
  43. Konus-Wind detection of GRB 250107D (short/hard)
  44. IPN triangulation of GRB 250107D (short/hard)
  45. IPN triangulation of GRB 250107C
  46. GRB 250108B: Gemini-North likely redshift z = 2.197
  47. GRB 250108B: Swift-BAT refined analysis
  48. GRB 250108B: 1.3m DFOT upper limit
  49. GRB 250108B: REM optical/NIR upper limits
  50. GRB 250109A /EP250109a: Fermi GBM Final Localization
  51. GRB 250107C: SVOM/GRM observation
  52. GRB 250101A: Terskol K-800 optical observations
  53. EP250109a: Swift/XRT non-detection
  54. GRB 250108A: Swift/UVOT Upper Limits
  55. GRB 250108A: NOT optical upper limit
  56. GRB 250108B: Swift-XRT refined Analysis
  57. Swift GRB 250108B: Global MASTER-Net observations report
  58. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  59. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  60. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  61. GRB 250103A: 1.6m Mephisto optical observations
  62. GRB 250108A: Swift-XRT afterglow detection
  63. GRB 250108A:SVOM/VT optical candidate
  64. GRB 250108B: Swift/UVOT Upper Limits
  65. GRB 250103A: Swift-XRT afterglow detection
  66. GRB 250108B: Enhanced Swift-XRT position
  67. GRB 250108B: Swift detection of a burst
  68. GRB 250108A: Swift ToO observations
  69. GRB 250108A: SVOM detection of a soft long burst
  70. GRB 250107A: Fermi GBM Observation
  71. GRB 241228B: Fermi-LAT detection
  72. Fermi GRB 250107B: Global MASTER-Net observations report
  73. GRB 250107A: Swift ToO observations
  74. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  75. GRB 250107B: Fermi GBM Final Real-time Localization
  76. GRB 250106A: SVOM/VT 2nd optical deep observation
  77. GRB 250101A: J band upper limit by SYSU 80cm telescope
  78. GRB 250107A: Fermi GBM Final Real-time Localization
  79. GRB 250106A: NOT optical observations
  80. GRB 250103B: REM optical/NIR upper limits
  81. GRB 250101A: REM optical/NIR counterpart detection
  82. GRB 250106A: Swift-XRT observations
  83. GRB 250106A: SVOM/VT optical candidate
  84. GRB 250106A: Swift ToO observations
  85. GRB 250106A: SVOM detection of a long burst
  86. GRB 241229A: SVOM/VT optical upperlimit
  87. GRB 250103B: Swift-XRT refined Analysis
  88. GRB 250103B: LCO/1m optical afterglow candidate detection
  89. GRB 250103A: Bassano Bresciano Observatory upper limit
  90. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  91. GRB 250103A: Swift-XRT observations
  92. GRB 250101A: 1.3m DFOT optical afterglow detection
  93. GRB 241229A: 1.3m DFOT upper limit
  94. GRB 241228B: 1.3m DFOT Optical observations
  95. GRB 241228A: 1.3m DFOT upper limit
  96. GRB 250103A: NOT spectroscopic redshift
  97. GRB 250103B:SVOM/VT optical counterpart
  98. GRB 250103A: Montarrenti Observatory optical detection
  99. GRB 250101A: further LCOGT optical afterglow observations
  100. GRB 250103A: Redshift 4.01 from OSIRIS+/GTC

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