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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').
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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"

45701 results found.

  1. GRB 250207B: Swift-XRT observations
  2. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  3. IceCube-250203A: No transient candidates from the Zwicky Transient Facility
  4. LIGO/Virgo/KAGRA S250206dm: Spectroscopic Classification of AT2025bay and AT2025baz with Keck I/LRIS
  5. LIGO/Virgo/KAGRA S250206dm: Candidates from the Zwicky Transient Facility
  6. LIGO/Virgo/KAGRA S250206dm: ePESSTO+ classification of AT2025bar
  7. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  8. GRB 250208A: Fermi GBM Final Real-time Localization
  9. EP250207a: EP-WXT detection and XRT follow-up observation
  10. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
  12. GRB 250207A: Swift-XRT refined Analysis
  13. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
  14. EP-WXT trigger 01709131361: correction to GCN 39214
  15. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  16. GRB 250207A: Enhanced Swift-XRT position
  17. CHIME/FRB source FRB 20250206A detected less than 1 minute after LIGO-Virgo-Kagra (LVK) S250206dm, however the probability of spatial coincidence is order 0.1%
  18. LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
  19. EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
  20. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  21. GRB 250207A: REM IR afterglow detection
  22. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  23. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  24. GRB 250207A: FRAM-Auger optical detection
  25. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  26. GRB 250207B: Tiled Swift observations
  27. LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
  28. Konus-Wind detection of GRB 250204B
  29. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  30. IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
  31. GRB 250207A: REM optical afterglow detection
  32. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  33. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  34. GRB 250207A: Swift/UVOT Detection
  35. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  36. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  37. LIGO/Virgo/KAGRA S250206dm: SOAR galaxy targeted observations
  38. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  39. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  40. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  41. GRB 250129A: Continued AbAO and Mondy optical observations
  42. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  43. GRB 250207B: MAXI/GSC detection
  44. The EP-WXT trigger 01709131347 is likely a flaring star
  45. The EP-WXT trigger 01709131332 is likely a flaring star
  46. The EP-WXT trigger 01709131290 is likely a flaring star
  47. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  48. LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
  49. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  50. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  51. GRB 250207A: Swift detection of a burst with optical counterpart
  52. GRB 250207A: Fermi GBM Final Real-time Localization
  53. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  54. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  55. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  56. LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
  57. LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
  58. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
  60. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  61. GRB 250206A: Fermi GBM Final Real-time Localization
  62. GRB 250205A: Fermi GBM Observation
  63. GRB 250205A: REM NIR upper limit
  64. EP250205a/GRB 250205A: FTW optical and NIR observations of the counterpart
  65. GRB 250205A: Swift/UVOT Upper Limits
  66. LIGO/Virgo/KAGRA S250205ee: Updated Sky localization and Source Classification
  67. EP250205a/GRB 250205A: correction to the source localization
  68. EP250205a/GRB 250205A: Einstein Probe observation
  69. GRB 250127C: SVOM/GRM observation of a burst
  70. GRB 250204B: SVOM/GRM observation of a likely short burst
  71. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  72. GRB 250205A: Swift/XRT detection
  73. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  74. GRB250205A: SVOM/VT optical afterglow detection
  75. GRB 250205A: GOTO optical upper limits
  76. GRB 250205A: OHP/T193 optical counterpart candidate
  77. GRB 250205A: Liverpool Telescope optical counterpart candidate detection
  78. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  79. GRB 250205A: SVOM detection of a burst
  80. LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
  81. Konus-Wind detection of GRB 250201A
  82. IPN triangulation of GRB 250201A
  83. LIGO/Virgo/KAGRA S250205bk: Updated Sky localization
  84. Konus-Wind detection of GRB 250202B
  85. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  86. GRB 250129A: Swift-BAT refined analysis
  87. EP 250108A: Upper limits from Fermi-GBM Observations
  88. IPN triangulation of GRB 250204B (short/hard)
  89. IPN triangulation of GRB 250202B
  90. LIGO/Virgo/KAGRA S250204ax: Updated Sky localization
  91. GRB 250204B: AstroSat CZTI detection of a short burst
  92. GRB 250204B: Fermi GBM Final Localization
  93. GRB 250129A: LCO late afterglow detection
  94. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  95. GRB 250204A: Fermi GBM Final Real-time Localization
  96. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  97. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  98. GRB 250202B: NuSTAR detection of the prompt emission
  99. GRB 250202C: GRBAlpha detection
  100. GRB 250202B: Fermi GBM Detection

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