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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"

26724 results found.

  1. GRB 250331D: Swift-XRT observations
  2. GRB 250331C: Swift-XRT refined Analysis
  3. GRB 250331B: Swift-XRT refined Analysis
  4. GRB 250331B: Swift-XRT refined Analysis
  5. GRB 250330B: SVOM/GRM observation of a short burst
  6. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  7. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  8. Konus-Wind detection of GRB 250327B
  9. GRB 250331C: Enhanced Swift-XRT position
  10. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 250331B: Enhanced Swift-XRT position
  12. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  13. GRB 250330A: VLT/FORS2 Afterglow Detection
  14. GRB20250327B: 45th Parallel Observatory upper limit
  15. GRB 250328A: Swift/UVOT Detection
  16. GRB 250328A: Swift-XRT refined Analysis
  17. Fermi-LAT gamma-ray observations of IceCube-250330A
  18. GRB 250330A: Fermi GBM Observation
  19. GRB 250331C: COLIBRÍ/DDRAGO optical upper limit
  20. GRB 250331B: COLIBRÍ/DDRAGO optical upper limit
  21. GRB 250331C: Swift detection of a burst
  22. GRB 250331B: Swift detection of a burst
  23. SVOM/sb25033102: SVOM detection of an X-ray transient
  24. LIGO/Virgo/KAGRA S250331o: Identification of a GW compact binary merger candidate
  25. GRB 250330A: Swift/UVOT Upper Limits
  26. GRB 250330A: Swift-XRT afterglow detection
  27. GRB 250328A: 1.6m Mephisto optical observations
  28. GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
  29. GRB 250330A: VLT/FORS2 Optical Observations
  30. GRB 250329B: Swift-XRT afterglow detection
  31. GRB 250330A: Swift detection of a burst
  32. GRB 250329B: SVOM/C-GFT optical upper limit
  33. GRB 250327B: SVOM/COLIBRÍ (F-GFT) Further Observations
  34. GRB 250329B: 1.6m Mephisto Optical Upper Limits
  35. LIGO/Virgo/KAGRA S250329fl: 2 counterpart neutrino candidate events from an IceCube neutrino search
  36. GRB250329A: REM optical afterglow detection
  37. GRB 250329B: SVOM detection of a faint transient
  38. GRB 250329A: Swift-XRT afterglow detection
  39. GRB 250328A: SVOM/VT optical observation
  40. GRB 250329A: Fading optical counterpart detection by LCO.
  41. GRB 250328A: SVOM/C-GFT optical upper limit
  42. GRB 250328A: SVOM/COLIBRÍ (F-GFT) optical afterglow candidate
  43. GRB 250328A: VLT/HAWK-I near-infrared afterglow candidate
  44. GRB 250329A: SVOM/VT optical counterpart confirmation
  45. GRB 250329A: SVOM detection of a burst
  46. GRB 250329A: SVOM/COLIBRÍ (F-GFT) Detection of a Bright Optical Counterpart Candidate
  47. GRB 250327B: J-band observations with WINTER
  48. GRB 250327B: LCO optical counterpart detection
  49. GRB 250328A: SVOM detection of a burst
  50. EP250302a: SPI-ACS/INTEGRAL Upper Limit
  51. GRB 250327B: CrAO and SAO RAS Optical Observations
  52. GRB 250327b: Liverpool Telescope optical observations
  53. GRB 250322A: GRANDMA/TNOT optical upper limits
  54. GRB 250327A: SVOM/VT upper limits on the XRT position
  55. LIGO/Virgo/KAGRA S250328ae: Identification of a GW compact binary merger candidate
  56. GRB 250327B: SVOM/COLIBRÍ (F-GFT) follow-up observations
  57. GRB 250327B: Las Cumbres optical counterpart detection
  58. GRB 250327B: Swift-XRT detection of the X-ray afterglow
  59. GRB 250327B: 1.6m Mephisto optical observations
  60. GRB 250327A: Swift-XRT refined Analysis
  61. GRB 250327B: SVOM/VT optically bright counterpart
  62. GRB 250327B: SAO RAS optical candidate
  63. GRB 250327B: SVOM detection of a burst
  64. FRB 20250316A: The sub-arcsecond localization of FRB 20250316A using CHIME/FRB Outriggers coincides with reported X-ray counterparts
  65. GRB 250327A: J-band observations with WINTER
  66. GRB 250327A: SVOM/VT optical candidate
  67. FRB 20250316A: Pan-STARRS r and i-band imaging and photometry
  68. GRB 250327A: Fermi GBM observation
  69. GRB 250327A: DDOTI Optical Observations
  70. GRB 250327A: COLIBRÍ optical upper limit
  71. Konus-Wind detection of GRB 250322A (short)
  72. IPN triangulation of GRB 250322B
  73. LIGO/Virgo/KAGRA S250326y: Identification of a GW compact binary merger candidate
  74. EP250321a: Mondy AZT-33IK Continued Optical Observations
  75. Swift follow-up observations of FRB250316A and EP J120944.2+585060
  76. GRB 250322A: third epoch of NOT optical observations
  77. GRB 250321B: ISON-Kitab RC-36 Optical Upper Limit
  78. FRB 250316A: NOT optical upper limit for the X ray source EP J120944.2+585060
  79. GRB 250322A: further NOT optical observations
  80. EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
  81. GRB 250322A: Swift/UVOT Upper Limits
  82. EP250324A: COLIBRÍ/DDRAGO Optical Observations
  83. GRB 250322A: VLT/X-shooter redshift confirmation of the putative host galaxy
  84. FRB 250316A: COLIBRÍ/DDRAGO Optical follow up of the X ray source EP J120944.2+585060
  85. GRB 250321B: Swift-XRT observations
  86. GRB 250322A: Swift-XRT refined Analysis
  87. EP250321a: TNOT Observation of Optical Counterpart
  88. FRB 250316A: DDOTI Continued Optical Observations (Third Epoch)
  89. SVOM/sb25032302: SVOM detection of a long X-ray transient
  90. GRB 250322B: AstroSat CZTI detection of a bright long burst
  91. GRB 250322A: VLT optical observations
  92. GRB 250322A: VLT near-infrared observations
  93. FRB 250316A: DDOTI Continued Optical Observations
  94. GRB 250322A: NOT optical upper limits
  95. GRB 250322A: Enhanced Swift-XRT position
  96. GRB 250321B: SVOM/COLIBRÍ (F-GFT) follow-up observations
  97. FRB 20250316A: Kinder optical upper limits of the Einstein Probe candidate X-ray source EP J120944.2+585060
  98. EP250321a: Liverpool Telescope optical follow-up
  99. EP250321a: Mondy AZT-33IK Optical Observations
  100. GRB 250322A: Swift detection of a short burst

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