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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"

4571 results found.

  1. GRB 240513A: Fermi GBM observation
  2. GRB 240513A: Swift-XRT observations
  3. LAT GRB240513.31: Global MASTER-Net observations report
  4. Fermi trigger No 737277727: Global MASTER-Net observations report
  5. Fermi trigger No 737247400: Global MASTER-Net observations report
  6. Fermi trigger No 737196587: Global MASTER-Net observations report
  7. Fermi trigger No 737168073: Global MASTER-Net observations report
  8. GRB 240511A: Swift-XRT refined Analysis
  9. Fermi trigger No 737173236: Global MASTER-Net observations report
  10. Fermi trigger No 737152719: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
  12. Fermi trigger No 736967879: Global MASTER-Net observations report
  13. Fermi trigger No 736564880: Global MASTER-Net observations report
  14. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  15. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  16. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  17. GRB 240503A: AstroSat CZTI detection
  18. Fermi GRB 240501A: Global MASTER-Net observations report
  19. Fermi trigger No 736197684: Global MASTER-Net observations report
  20. GRB 240426A: VZLUSAT-2 detection
  21. GRB 240407A: VZLUSAT-2 detection
  22. Fermi-LAT gamma-ray observations of IceCube-240424A
  23. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  24. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  25. GRB 240426A: AstroSat CZTI detection
  26. LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
  27. LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
  28. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  29. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  30. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  31. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  32. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  33. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  34. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
  35. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  36. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  37. LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
  38. Fermi trigger No 735697285: Global MASTER-Net observations report
  39. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  40. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  41. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  42. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  43. LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
  44. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  45. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  46. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  47. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of Mag24a
  48. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  49. LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
  50. IceCube Alert 240424.08: Global MASTER-Net observations report
  51. LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
  52. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  53. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  54. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  55. Fermi trigger No 735470374: Global MASTER-Net observations report
  56. Fermi GRB 240422A: Global MASTER-Net observations report
  57. GRB 240422A: Fermi GBM Final Real-time Localization
  58. GRB 240421B: Swift-XRT refined Analysis
  59. EP240420a: Xinglong decaying optical counterpart
  60. Fermi trigger No 735280430: Global MASTER-Net observations report
  61. IceCube Alert 240419.98: Global MASTER-Net observations report
  62. GRB 240419B: Swift-XRT refined Analysis
  63. Swift GRB 240419A: Global MASTER-Net observations report
  64. GRB 240419A: Swift-XRT refined Analysis
  65. GRB 240418A: Swift-XRT refined Analysis
  66. GRB 240418A: Swift detection of a burst
  67. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  68. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  69. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  70. EP 240414a: BOOTES-4/MET Optical Upper Limits
  71. Fermi GRB 240415A: Global MASTER-Net observations report
  72. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  73. Swift Trigger 1220736: detection of 4U 1543-62.
  74. Fermi GRB 240407A: Global MASTER-Net observations report
  75. LXT 240402A: MASTER optical observations with AGN in error-box
  76. Fermi GRB 240402A: Global MASTER-Net observations report
  77. X-ray transient EP20240331a: MeerLICHT optical upper limits
  78. GRB 240324A: AstroSat CZTI detection of a short burst
  79. Fermi GRB 240328B: Global MASTER-Net observations report
  80. Fermi GRB 240328A: Global MASTER-Net observations report
  81. X-ray transient EP240315a: continued ATCA monitoring
  82. Fermi trigger No 733092476: Global MASTER-Net observations report
  83. Fermi trigger No 732937833: Global MASTER-Net observations report
  84. Fermi GRB 240320A: Global MASTER-Net observations report
  85. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  86. GRB 240317B: Swift/BAT-GUANO Angular Error Correction
  87. X-ray transient EP240315a: Montarrenti Observatory optical upper limit
  88. Fermi GRB 240317B: Global MASTER-Net observations report
  89. Fermi GRB 240317A: Global MASTER-Net observations report
  90. GRB 240317B: Fermi GBM Final Real-time Localization
  91. Fermi trigger No 732299243: Global MASTER-Net observations report
  92. GRB 240309A: MAXI/GSC detection
  93. GRB 231215A: further radio observations with the VLA
  94. Fermi GRB 240306A: Global MASTER-Net observations report
  95. Fermi GRB 240305A: Global MASTER-Net observations report
  96. Improved IPN triangulation of GRB 240227A (short)
  97. Fermi trigger No 731161136: Global MASTER-Net observations report
  98. Fermi GRB 240229A: Global MASTER-Net observations report
  99. GRB 240225B : MITSuME Akeno optical afterglow candidate detection
  100. Swift J1727.8-1613 (GRB 230824A): Madrona Peak Observatory - optical follow-up

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