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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"

18515 results found.

  1. GRB 250217C: SVOM/GRM observation
  2. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  3. GRANDMA/OPD observations of GRB250215A
  4. The EP-WXT trigger 01709131775 is likely a flaring star
  5. GRB 250215A / EP250215a: LCO detection of the afterglow
  6. GRB 250215A: Swift/UVOT Upper Limits
  7. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  8. GRB 250215A: Fermi GBM Observation
  9. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  10. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  11. GRB 250215A: SVOM/GRM observation
  12. EP250215a / GRB 250215A: AstroSat CZTI detection
  13. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  14. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  15. EP250207b: Xinglong optical upper limit
  16. EP250212a: Xinglong optical upper limit
  17. LIGO/Virgo/KAGRA S250206dm: DECam GW-MMADS candidates
  18. GRB 250205A: VIRT Optical Upper Limit
  19. GRB 250205A: Leavitt Observatory optical upper limit
  20. EP250207B: Chandra localization of the X-ray counterpart
  21. EP250212a: Liverpool Telescope optical upper limits
  22. EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  23. GRB250101A: Radio upper limits from GMRT observations
  24. EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit
  25. EP250207B: GTC z-band Observations
  26. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  27. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  28. EP250207b: NOT optical counterpart candidate
  29. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  30. LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST
  31. GRB 250205A / EP250205A: radio detection with the VLA
  32. EP250207b: Tentative z-band brightening source
  33. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  34. Konus-Wind detection of GRB 250206A
  35. GRB 250210A: SVOM/GRM observation of a long burst
  36. EP250207b: Liverpool Telescope possible optical counterpart
  37. LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
  38. GRB 250207A: Skynet optical afterglow observations
  39. GRB 241128A: VIRT Optical Upper Limit
  40. EP250207b: Gemini GMOS-N z-band observations
  41. EP250207b: a new X-ray transient detected by Einstein Probe
  42. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  43. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  44. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  45. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  46. GRB 250207A: 1.3m DFOT Optical observations
  47. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  48. GRB 250129A: GRANDMA Continued Afterglow Detection
  49. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  50. GRB 250205A: 1.3m DFOT optical upper limit
  51. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  52. GRB 250207B: Swift-XRT observations
  53. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  54. EP250207a: EP-WXT detection and XRT follow-up observation
  55. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  56. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  57. GRB 250207A: Enhanced Swift-XRT position
  58. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  59. GRB 250207A: REM IR afterglow detection
  60. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  61. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  62. GRB 250207A: REM optical afterglow detection
  63. GRB 250207A: Swift/UVOT Detection
  64. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  65. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  66. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  67. GRB 250129A: Continued AbAO and Mondy optical observations
  68. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  69. The EP-WXT trigger 01709131347 is likely a flaring star
  70. The EP-WXT trigger 01709131332 is likely a flaring star
  71. The EP-WXT trigger 01709131290 is likely a flaring star
  72. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  73. GRB 250207A: Swift detection of a burst with optical counterpart
  74. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  75. GRB 250205A: REM NIR upper limit
  76. GRB 250205A: Swift/UVOT Upper Limits
  77. EP250205a/GRB 250205A: Einstein Probe observation
  78. GRB 250127C: SVOM/GRM observation of a burst
  79. GRB 250204B: SVOM/GRM observation of a likely short burst
  80. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  81. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  82. GRB250205A: SVOM/VT optical afterglow detection
  83. GRB 250205A: OHP/T193 optical counterpart candidate
  84. GRB 250205A: SVOM detection of a burst
  85. IPN triangulation of GRB 250201A
  86. Konus-Wind detection of GRB 250202B
  87. IPN triangulation of GRB 250202B
  88. GRB 250129A: LCO late afterglow detection
  89. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  90. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  91. GRB 250129a: Liverpool Telescope optical follow-up
  92. GRB 240129A: further SAO RAS optical observations
  93. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  94. The EP-WXT trigger 01709131196 is likely a flaring star
  95. GRB 250129A: SVOM/C-GFT optical observations
  96. Swift GRB250129A: MASTER 4 days observations report
  97. GRB 250129A: 1.3m DFOT Optical observations
  98. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  99. GRB 250129A: SAO RAS optical observations
  100. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow

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