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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"

45746 results found.

  1. GRB 250403A: Montarrenti Observatory optical detection
  2. GRB 250404A: Fermi GBM Detection
  3. EP250404a: Global MASTER-Net observations report
  4. GRB 250403A: KAIT optical observations
  5. EP250404a: AKO Optical Afterglow Detection
  6. EP250404a: LAST detection of optical counterpart
  7. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  8. EP250404a: Xinglong-2.16m spectroscopic redshift
  9. GRB 250403A: Fermi GBM observations
  10. GRB 250327B: VIRT Optical Upper Limit
  11. EP250404a: Mephisto multi-band optical detection
  12. GRB 250331C Swift-BAT refined analysis
  13. GRB 250331B Swift-BAT refined analysis
  14. GRB 250330A Swift-BAT refined analysis
  15. EP250321A: J band upper limit by SYSU 80cm telescope
  16. EP250404a: BOOTES-4/JGT optical afterglow detection
  17. EP250404a: Nanshan/HMT optical counterpart detection
  18. EP250404a: Einstein Probe detection of an X-ray transient
  19. GRB 250404A: Fermi GBM Final Real-time Localization
  20. GRB 250402A: Mondy optical observations
  21. GRB 250403A: Swift/UVOT Detection
  22. GRB 250402A: Swift/UVOT Upper Limits
  23. EP250402a: Optical upper limit with Kinder observations
  24. GRB 250403A: SVOM/VT optical observation
  25. GRB 250403A: REM NIR afterglow detection
  26. GRB 250403A: LCO optical counterpart detection
  27. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  28. GRB 250403A: JinShan optical observations
  29. GRB 250402A: EP-FXT afterglow detection
  30. GRB 250403A: Optical counterpart detection by LCO.
  31. EP250402a: EP-FXT follow-up observations
  32. GRB 250403A: Swift-XRT observations
  33. GRB 250322A: 10 GHz VLA radio upper limits
  34. Fermi GRB 250403A: Global MASTER-Net observations report
  35. GRB 250403A: GOTO optical counterpart follow-up observations
  36. GRB 250402A: NUTTelA-TAO Early Optical Limits
  37. GRB 250403A: GMG Optical Observation
  38. GRB 250403A: 1.6m Mephisto multi-band optical detection
  39. GRB 250402A: Fermi GBM Observation
  40. GRB 250403A: SVOM/C-GFT optical observations
  41. GRB 250403A: GOTO detection of the optical afterglow
  42. GRB 250402A: Swift-XRT observations
  43. GRB 250403A : SVOM detection of a burst
  44. GRB 250403A: Fermi GBM Final Real-time Localization
  45. GRB 250225B: VLT host galaxy redshift z = 0.950
  46. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  47. GRB 250402A: VLT/FORS2 spectroscopic redshift z = 2.823
  48. GRB 250402A: REM optical/NIR upper limits
  49. GRB 250402A: LCO optical counterpart detection
  50. GRB 250402A: refined SVOM/MXT data analysis
  51. The EP-WXT trigger 01709133862 is a flaring star
  52. EP250402a: Einstein Probe detection of a fast X-ray transient
  53. GRB 250402B: AstroSat CZTI detection of a short burst
  54. GRB 250402A: SVOM/VT optical counterpart
  55. GRB 250402A: SVOM detection of a burst
  56. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  57. GRB 250314A: ALMA detection
  58. GRB 250329B: Swift/UVOT Upper Limit
  59. GRB 250329A: Swift/UVOT Upper Limit
  60. GRB 250327B: Swift/UVOT Detection
  61. GRB 250327A: Swift/UVOT Upper Limits
  62. GRB 250331E: SVOM/GRM observation
  63. GRB 250327B: Kilonova-Catcher Observations
  64. GRB250331D: AbAO optical observations
  65. GRB 250331D: Fermi GBM observation
  66. GRB 250331C: Swift/UVOT Upper Limits
  67. GRB 250331B: Swift/UVOT Upper Limits
  68. GRB 250328A: AbAO AS-32 Optical Observations
  69. GRB 250219A: NOT candidate host galaxy detection
  70. GRB 250322B: GRBAlpha detection
  71. GRB 250331D: Swift-XRT observations
  72. GRB 250331C: Swift-XRT refined Analysis
  73. GRB 250331B: Swift-XRT refined Analysis
  74. GRB 250331B: Swift-XRT refined Analysis
  75. GRB 250322B possible detection by the AstroSat Satellite
  76. GRB 250330B: SVOM/GRM observation of a short burst
  77. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  78. Fermi GRB 250331E: Global MASTER-Net observations report
  79. Fermi GRB 250331D: Global MASTER-Net observations report
  80. GRB 250330B: EIRSAT-1 GMOD Detection
  81. GRB 250331E: Fermi GBM Final Real-time Localization
  82. GRB 250327A Swift-BAT refined analysis
  83. LIGO/Virgo/KAGRA S250331o: Updated Sky localization
  84. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  85. Fermi trigger No 765078057: Global MASTER-Net observations report
  86. GRB 250329B: CAHA 2.2m telescope optical limit
  87. GRB 250331D: Swift ToO observations
  88. Swift GRB 250331C: Global MASTER-Net observations report
  89. Swift GRB 250331B: Global MASTER-Net observations report
  90. GRB 250331D: Swift/BAT-GUANO arcminute localization of a burst during slew
  91. Konus-Wind detection of GRB 250327B
  92. GRB 250331C: Enhanced Swift-XRT position
  93. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  94. LIGO/Virgo/KAGRA S250331o: NED Galaxies in the 3-Initial Localization Volume
  95. GRB 250331B: Enhanced Swift-XRT position
  96. GRB 250320C : SVOM detection of a burst through offline search
  97. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  98. GRB 250329B: Swift-XRT confirmation of fading
  99. GRB 250330A: VLT/FORS2 Afterglow Detection
  100. GRB20250327B: 45th Parallel Observatory upper limit

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