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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"

28247 results found.

  1. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  2. EP251021b: Einstein Probe detection of a fast X-ray transient
  3. LIGO/Virgo/KAGRA S251021u: Updated Sky localization
  4. LIGO/Virgo/KAGRA S251021u: Identification of a GW compact binary merger candidate
  5. LIGO/Virgo/KAGRA S251018bi: Updated Sky localization
  6. Fermi-LAT gamma-ray observations of IceCube-251018A
  7. GRB 251017A : RAPAS follow-up observations
  8. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  9. GRB 251017A: COLIBRÍ optical observations of a late plateau
  10. IceCube-251018A: DDOTI Optical Upper Limit
  11. GRB 251017A: Swift-BAT refined analysis
  12. GRB 251018A: Fermi GBM Observation
  13. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  14. GRB 251018A: Swift-XRT refined Analysis
  15. GRB 251018A: Enhanced Swift-XRT position
  16. LIGO/Virgo/KAGRA S251018bi: Identification of a GW compact binary merger candidate
  17. GRB 251016A: Swift-XRT afterglow detection
  18. GRB 251017A: Swift/UVOT Detection
  19. GRB 251016A: Swift/UVOT Detection
  20. GRB 251018A: Swift/UVOT Detection
  21. GRB 251016A: VLT/FORS2 Optical Observation
  22. GRB 251017A: COLIBRÍ photometric redshift
  23. GRB 251017A: Swift-XRT refined Analysis
  24. GRB 251018A: MASTER OT detection
  25. GRB 251018A: TRT optical afterglow detection
  26. GRB 251018A: Swift detection of a burst with an optical counterpart
  27. GRB 251011A: Fermi GBM Observation
  28. GRB 251017A: J-band detection with WINTER
  29. GRB 251017A: Glowbug gamma-ray detection
  30. GRB 251013C: Liverpool Telescope observations
  31. GRB 251013C: Leavitt Observatory optical photometry
  32. GRB 251017A: JinShan observations of the optical afterglow
  33. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  34. GRB 251016A: AstroSat CZTI detection of a short burst
  35. GRB 251017A: Enhanced Swift-XRT position
  36. GRB 251017A: COLIBRÍ Early Afterglow Detection
  37. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  38. GRB 251017A: Swift detection of a burst with an optical counterpart
  39. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  40. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) observations of a strong and late rebrightening of the optical counterpart
  41. GRB 251007B: Swift-BAT refined analysis
  42. GRB 251014D: Swift-BAT refined analysis
  43. GRB 251016A: BOOTES-6/DPRT optical upper limit
  44. GRB 251016A: Glowbug gamma-ray detection of a short burst
  45. sb25101602: Swift-XRT counterpart detection
  46. GRB 251014A: Swift-XRT observations
  47. LIGO/Virgo/KAGRA S251014cn: Updated Sky localization
  48. GRB 251014B: PRIME J-band upper limit
  49. Upper limits from a search for additional neutrino events in IceCube
  50. IceCube Alert 251014.77: Global MASTER-Net observations report
  51. GRB 251013C: Kilonova-Catcher optical afterglow detection
  52. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  53. GRB 251013D: Swift/UVOT Observations
  54. GRB 251013C: Swift/UVOT Detection
  55. GRB 251013C: detection of a radio counterpart at 15.5GHz
  56. GRB 251013D: Swift-XRT observations
  57. Swift Trigger 1404295: possible GRB 251015A
  58. GRB 251014B: Swift-XRT observations
  59. GRB 251014B: Swift/UVOT Upper Limits
  60. GRB 251014B: VLT/FORS2 Optical Observation
  61. GRB 251014D: Swift/UVOT Upper Limits
  62. GRB 251014D: Swift-XRT afterglow detection
  63. GRB 251013C: MAO/AZT-22 optical observations
  64. GRB 251011B: SVOM/VT optical upper limit
  65. GRB 251013D: Fermi GBM Observation
  66. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) further multi-band optical observations
  67. GRB 251014A: Swift-BAT refined analysis
  68. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  69. GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  70. GRB 251014D: Swift detection of a burst
  71. GRB 251014A: PRIME near-infrared upper limits
  72. GRB 251014A: Glowbug gamma-ray detection of a likely short burst
  73. GRB 251014A: VLT/FORS2 Optical Observation
  74. GRB 251012A: Glowbug gamma-ray detection of a likely short burst
  75. GRB 251013C: MarSEC, optical afterglow photometry
  76. GRB 251013C: OHP/T193 optical afterglow photometry and spectroscopy
  77. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  78. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  79. GRB 251013C: Bassano Bresciano Observatory optical observations
  80. GRB 251013C: Early and late-time optical counterpart detection by LCO
  81. LIGO/Virgo/KAGRA S251014cn: NED Galaxies in the 3-Initial Localization Volume
  82. GRB 251013C: Fermi GBM Observation
  83. GRB 251014A: DDOTI Upper Limit
  84. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  85. LIGO/Virgo/KAGRA S251014cn: Identification of a GW compact binary merger candidate
  86. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  87. GRB 251013C: Asiago optical observations
  88. GRB 251013C: ABObservatory optical observations
  89. GRB 251014A: SAO RAS optical upper limit
  90. GRB 251014A: Fermi GBM Observation
  91. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  92. GRB 251013C: EP-FXT counterpart detection
  93. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  94. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  95. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  96. GRB 251013C: DDOTI detection of the optical afterglow
  97. GRB 251013C: Swift-XRT counterpart detection
  98. GRB 251013C: SAO RAS optical observations
  99. GRB 251013C: LCO optical afterglow detection
  100. GRB 251013C: Optical Observations via Virtual Telescope Project, Italy

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