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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"

24598 results found.

  1. GRB 231216A: optical upper limits from the INAF Asiago Observatory
  2. GRB 231215A: AMI-LA radio detection
  3. GRB 231216A: Nanshan/HMT optical upper limit
  4. GRB 231216A: LCOGT Optical Upper Limits
  5. GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
  6. GRB 231216A: Swift-XRT refined analysis correction
  7. GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
  8. GRB 231216A: Swift-XRT refined Analysis
  9. GRB 231216A: REM NIR upper limits
  10. GRB 231216A: Swift/UVOT Upper Limits
  11. GRB 231216A: Swift-BAT refined analysis
  12. GRB 231215A: Swift-BAT refined analysis
  13. GRB 231214A: Swift-BAT refined analysis
  14. GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
  15. GRB 231216A: GIT optical upper limit
  16. GRB 231216A: Swift detection of a burst
  17. Konus-Wind detection of GRB 231215A
  18. GRB 231214A: Swift/UVOT Upper Limits
  19. GRB 231205B: VZLUSAT-2 detection
  20. GRB 231204A: VZLUSAT-2 detection
  21. GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
  22. GRB 231215A: Fermi GBM observation
  23. GRB 231215A : OHP/T193 optical afterglow detection
  24. GRB 231215A: Swift/UVOT Detection
  25. LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search
  26. GRB 231215A: Swift-XRT refined Analysis
  27. GRB 231215A: AKO Optical Upper Limit
  28. GRB 231214A: Fermi GBM observation
  29. GRB 231215A: Enhanced Swift-XRT position
  30. Fermi trigger No 724326442: Global MASTER-Net observations report
  31. GRB 231214A: REM optical/NIR upper limits
  32. GRB 231215A: GROWTH-India optical follow-up
  33. GRB 231215A : Nanshan/HMT optical observations
  34. GRB 231215A: AstroSat CZTI detection
  35. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  36. GRB 231214A: Swift-XRT refined Analysis
  37. GRB 231215A: Mondy optical bright afterglow detection
  38. GRB 231214A: AstroSat CZTI detection
  39. GRB 231215A: Swift-XRT observations
  40. GRB 231215A: Swift detection of a burst
  41. GRB 231214A: Enhanced Swift-XRT position
  42. GRB 231214B: Swift/BAT-GUANO detection of a burst
  43. GRB 231214A: Swift detection of a burst
  44. GRB 231210B: REM optical/NIR upper limits
  45. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  46. LIGO/Virgo/KAGRA S231213ap: Updated Sky localization
  47. LIGO/Virgo/KAGRA S231213ap: Identification of a GW compact binary merger candidate
  48. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  49. LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
  50. LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
  51. GRB 231212A: GECAM-C detection of a likely short burst
  52. GRB 231210B: MeerLICHT afterglow observations
  53. GRB 231210B: Swift-BAT refined analysis
  54. GRB 231210B: Swift-XRT refined Analysis
  55. GRB 231210B: Enhanced Swift-XRT position
  56. GRB 231210B: VLT/X-shooter redshift
  57. GRB 231210B: Swift detection of a burst with optical counterpart
  58. Swift GRB231210.90: Global MASTER-Net OT detection
  59. IPN triangulation of GRB 231129C
  60. GRB231205B: Swift/UVOT Upper Limits
  61. GRB 231208A: Glowbug gamma-ray detection
  62. LIGO/Virgo/KAGRA S231206ca: Updated Sky localization
  63. GRB 231205B: Swift-BAT refined analysis
  64. GRB 231205B: 1.3m DFOT Optical upper limit
  65. LIGO/Virgo/KAGRA S231206cc: Updated Sky localization and Source Classification
  66. GRB 231206A: joint location of multiple instruments by ETJASMIN
  67. GRB 231205B: optical upper limit in TSHAOand AbAO
  68. LIGO/Virgo/KAGRA S231206cc: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S231206ca: Identification of a GW compact binary merger candidate
  70. GRB231115A: TURBO Pre-Burst Optical Upper Limits
  71. GRB 231205B: Swift-XRT refined Analysis
  72. Fermi-LAT gamma-ray observations of IceCube-231202A
  73. GRB 231205B: REM optical/NIR upper limits
  74. GRB 231129C: ASIM MXGS observation and localization
  75. GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
  76. GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  77. GRB 231205B : MITSuME Akeno optical upper limits
  78. GRB 231206A: GECAM-B detection of a short burst
  79. GRB 231205B: Zadko observatory - Gingin optical observations
  80. GRB 231205B: Gaoyazi/GOT optical upper limit
  81. GRB 231205B: Nanshan/HMT optical upper limit
  82. GRB 231205B: LCOGT Optical Upper Limits
  83. GRB 231205A: DDOTI Upper Limits on the Afterglow
  84. LIGO/Virgo/KAGRA S231205c: One counterpart neutrino candidate event from an IceCube neutrino search
  85. GRB 231205B: Enhanced Swift-XRT position
  86. GRB 231204A: Glowbug gamma-ray detection
  87. Fermi-LAT daily aperture light curve of T CrB now available
  88. GRB 231205B: AKO Optical Upper Limit
  89. GRB 231205B: Swift detection of a burst
  90. GRB 231205A: joint location of multiple instruments by ETJASMIN
  91. GRB 231205A: GECAM-B detection of a short burst
  92. Fermi trigger No 723326169: Global MASTER-Net observations report
  93. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  94. IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
  95. GRB 231203A: Fermi GBM Observation
  96. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  97. GRB 231129C: Swift-XRT afterglow detection
  98. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  99. GRB 231129A: VZLUSAT-2 detection
  100. GRB 231129B: Swift-XRT observations

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