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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"
  1. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  2. Additional DECam GW-MMADS Candidates from three nights of observations
  3. GRB 240425A: GRBAlpha detection
  4. Fermi-LAT gamma-ray observations of IceCube-240424A
  5. LIGO/Virgo/KAGRA S240426s: Updated Sky localization
  6. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  7. LIGO/Virgo/KAGRA S240426dl: Updated Sky localization
  8. GRB 240429A: Fermi GBM Final Real-time Localization
  9. LIGO/Virgo/KAGRA S240428dr: Updated Sky localization
  10. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
  11. LIGO/Virgo/KAGRA S240429an: Retraction of GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  13. LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
  14. Fermi GRB 240428A: Global MASTER-Net observations report
  15. GRB 240428A: Fermi GBM Final Real-time Localization
  16. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a
  17. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  18. EP240426b: AST3-2 optical upper limit
  19. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  20. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  21. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  22. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  23. EP240426b: EP-WXT detection of a new fast X-ray transient
  24. LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a
  25. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
  26. LIGO/Virgo/KAGRA S240422ed: BOOTES-6/DPRT optical upper limits for EP240426a
  27. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  28. LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
  29. GRB 240426A: AstroSat CZTI detection
  30. EP240426a: YAHPT optical upper limit
  31. XMM-Newton observation of EP240426a
  32. LIGO/Virgo/KAGRA S240426dl: Identification of a GW compact binary merger candidate
  33. LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
  34. LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
  35. GRB 240414A: NOEMA detection
  36. LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
  37. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  38. EP240426a: GMG optical upper limit
  39. LVK S240422ed: Further Swift-XRT followup of three sources
  40. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  41. LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate
  42. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  43. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  44. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  45. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
  46. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  47. LIGO/Virgo/KAGRA S240422ed: PRIME near-infrared observations
  48. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  49. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  50. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
  51. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  52. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  53. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  54. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  55. LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
  56. LIGO/Virgo/KAGRA S240422ed: ANU 2.3m followup of candidate counterparts
  57. LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN
  58. GRB 240425A: Fermi GBM Final Real-time Localization
  59. Fermi trigger No 735697285: Global MASTER-Net observations report
  60. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  61. GRB 240419B: Swift-BAT refined analysis
  62. GRB 240421B: Swift-BAT refined analysis
  63. GRB 240422A: Glowbug gamma-ray detection
  64. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  65. LIGO/Virgo/KAGRA S240413p: DESGW DECam Follow-Up
  66. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  67. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  68. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  69. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  70. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  71. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  72. LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
  73. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  74. LIGO/Virgo/KAGRA S240422ed: MOSFIRE imaging of the DECam GW-MMADS candidate AT 2024hdm
  75. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  76. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  77. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of Mag24a
  78. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  79. LIGO/Virgo/KAGRA S240422ed: Archival DECaPSs2 observations of the field of Mag24a
  80. LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
  81. LIGO/Virgo/KAGRA S240422ed: Potential Magellan candidates from GCN 36263 are unrelated.
  82. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  83. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  84. GRB 240421B: GRBAlpha detection
  85. IceCube Alert 240424.08: Global MASTER-Net observations report
  86. LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart
  87. LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
  88. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  89. LIGO/Virgo/KAGRA S240422ed: LAST optical observations
  90. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  91. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  92. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  93. LIGO/Virgo/KAGRA S240421ar: Updated Sky localization
  94. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  95. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
  96. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  97. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  98. GRB 240419A: Swift-BAT refined analysis
  99. GRB 240418A: Swift-BAT refined analysis
  100. LXT240402A/GRB240402B: Chandra X-ray detection

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