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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"

20506 results found.

  1. GRB 250327A: J-band observations with WINTER
  2. GRB 250327A: SVOM/VT optical candidate
  3. FRB 20250316A: Pan-STARRS r and i-band imaging and photometry
  4. GRB 250327A: DDOTI Optical Observations
  5. GRB 250327A: COLIBRÍ optical upper limit
  6. IPN triangulation of GRB 250322B
  7. LIGO/Virgo/KAGRA S250326y: Identification of a GW compact binary merger candidate
  8. EP250321a: Mondy AZT-33IK Continued Optical Observations
  9. Swift follow-up observations of FRB250316A and EP J120944.2+585060
  10. GRB 250322A: third epoch of NOT optical observations
  11. GRB 250321B: ISON-Kitab RC-36 Optical Upper Limit
  12. FRB 250316A: NOT optical upper limit for the X ray source EP J120944.2+585060
  13. GRB 250322A: further NOT optical observations
  14. EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
  15. GRB 250322A: Swift/UVOT Upper Limits
  16. EP250324A: COLIBRÍ/DDRAGO Optical Observations
  17. FRB 250316A: COLIBRÍ/DDRAGO Optical follow up of the X ray source EP J120944.2+585060
  18. GRB 250321B: Swift-XRT observations
  19. EP250321a: TNOT Observation of Optical Counterpart
  20. FRB 250316A: DDOTI Continued Optical Observations (Third Epoch)
  21. GRB 250322A: VLT optical observations
  22. GRB 250322A: VLT near-infrared observations
  23. FRB 250316A: DDOTI Continued Optical Observations
  24. GRB 250322A: NOT optical upper limits
  25. GRB 250322A: Enhanced Swift-XRT position
  26. GRB 250321B: SVOM/COLIBRÍ (F-GFT) follow-up observations
  27. FRB 20250316A: Kinder optical upper limits of the Einstein Probe candidate X-ray source EP J120944.2+585060
  28. EP250321a: Liverpool Telescope optical follow-up
  29. EP250321a: Mondy AZT-33IK Optical Observations
  30. GRB 250322A: Swift detection of a short burst
  31. FRB 20250316A: detection of a candidate associated X-ray source EP J120944.2+585060 by Einstein Probe
  32. EP250321a: refined analysis of the EP-WXT and EP-FXT observations
  33. EP250321a: KAIT optical observations
  34. EP250321A: COLIBRÍ Continuing Optical Observations
  35. EP250321a: WFST optical observations
  36. EP250321a: Xinglong 216 decaying optical observations
  37. GRB 250321A: Swift-XRT refined Analysis
  38. EP 250321A: Optical counterpart detection by LCO.
  39. EP250321a: Kinder optical follow-up observations
  40. GRB 250321A: Swift/UVOT Upper Limits
  41. GRB 250320B: SVOM/GRM observation of a long burst
  42. EP250321a: LCO optical counterpart detection
  43. EP250321A: COLIBRÍ Optical Observations
  44. GRB 250320B: AstroSat CZTI detection
  45. EP250321a: REM optical/NIR afterglow detection
  46. EP250321a: TRT optical counterpart detection
  47. EP250321a: Einstein Probe detection of an X-ray transient
  48. GRB 250321A: GOTO optical upper limits
  49. GRB 250314A: Keck/NIRC2 J-band upper limit
  50. EP250226a/GRB 250226A: KAIT optical observations
  51. GRB 250321A: Swift detection of a burst
  52. GRB 250309B: Proof-of-concept for Joint ZTF+EP Experiment
  53. GRB 250317B: Mondy AZT-33IK Continued Optical Observations
  54. GRB 250317B: SVOM/COLIBRI (F-GFT) follow-up observations
  55. EP250302a: VLA observations
  56. LIGO/Virgo/KAGRA S250319bu: Identification of a GW compact binary merger candidate
  57. GRB 250317C: SVOM/GRM observation of a long burst
  58. GRB 250317B: Leavitt Observatory optical upper limit
  59. GRB 250317B: Mondy AZT-33IK Optical Observations
  60. GRB 250317B: NOT optical observations suggest an optical plateau phase
  61. GRB 250317B: OHP/T193 optical observations
  62. GRB250312A: Swift/UVOT Upper Limits
  63. GRB 250317B: REM optical/NIR observations
  64. GRB 250316A: Swift/UVOT Upper Limits
  65. GRB 250314A: REM optical/NIR upper limits
  66. GRB 250316A: AbAO AS-32 Optical Upper Limit
  67. EP 250317B: Fading optical counterpart detection by LCO
  68. GRB 250316A: Swift-XRT afterglow detection
  69. GRB 250317B: LCO detection of the fading optical afterglow
  70. GRB 250317B: SVOM/VT detection of an optical candidate from VHF data
  71. GRB 250317B: SVOM/F-GFT (COLIBRÍ) Detection of a Fading Optical Counterpart
  72. GRB 250317B: SVOM detection of a burst / correction to GRB name of GCN 39752
  73. GRB 250317B: SVOM detection of a burst
  74. EP250315a: refined analysis of the EP-WXT and EP-FXT observations
  75. GRB 250314A: Swift/UVOT Upper Limits
  76. GRB 250314A: Swift XRT Detection
  77. EP250315a: optical counterpart candidate detected by Gemini North
  78. GRB 250314A: VLT/X-shooter dropout, redshift z ~ 7.3
  79. EP250315a: Einstein Probe detection of an X-ray transient
  80. GRB 250226A: Mondy AZT-33IK and Koshka Zeiss-1000 Optical Upper Limits
  81. SVOM/MXT upper limit on GRB 250314A
  82. GRB 250314A: SVOM/VT upper limit
  83. GRB 250314A: NOT near-infrared candidate counterpart
  84. GRB 250313A: Fermi GBM Detection
  85. GRB 250313A: Swift-XRT observations
  86. GRB250314A: SVOM/VT lack of bright optical candidate from VHF data
  87. Konus-Wind detection of GRB 250313A
  88. GRB 250314A: SVOM detection of a burst
  89. EP250304a: Pan-STARRS r and i-band imaging and photometry
  90. GRB 250312B: Swift/BAT-GUANO localization skymap of a burst
  91. GRB 250309B: PRIME near-infrared upper limits in 2nd epoch
  92. GRB 250312A: Enhanced Swift-XRT position
  93. GRB 250309B/AT2025dws: Daochen/RC-10 optical counterpart observation
  94. GRB 250312A: Swift detection of a burst
  95. GRB 241213A: VIRT Optical Upper Limit
  96. GRB 241228A: VIRT Optical Upper Limit
  97. GRB 250311A/EP250311a: Optical upper limits with Kinder observations
  98. GRB 250311A: Swift-XRT observations
  99. GRB 250309B: 1.3m DFOT Optical observations
  100. IceCube-250309A: Upper limits from a search for additional neutrino events in IceCube

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