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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"

20415 results found.

  1. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  2. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  3. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  4. EP251118a: FTW optical and NIR observations
  5. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  6. EP251118a: VLT near-infrared observation
  7. GRB 251116D: SVOM/GRM observation of a long GRB
  8. GRB 251119A: SVOM detection of a possible burst
  9. EP251118a: NOT candidate optical counterpart
  10. EP251118a: Einstein Probe detected of a fast X-ray transient
  11. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  12. GRB 251116C: SVOM/ECLAIRs refined analysis
  13. GRB 251116B: SVOM/ECLAIRs refined analysis
  14. GRB 251116D: Insight-HXMT/HE detection
  15. GRB 251115A: Swift-XRT observations
  16. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  17. GRB 251117A: SVOM/GRM observation of a short burst
  18. GRB 251117A: Fermi-LAT detection
  19. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  20. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  21. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  22. EP251023a: Assy AZT-20 optical observations
  23. EP251023a: UAFO and AbAO optical observations
  24. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  25. GRB 251025B: further Mondy optical observations
  26. GRB 251111A: Mondy optical upper limit
  27. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  28. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  29. GRB 251116B: LCO optical upper limits
  30. GRB 251116C: LCO optical upper limits
  31. GRB 251116C: SVOM detection of a burst
  32. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  33. GRB 251115A: Fermi-LAT detection
  34. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  35. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  36. GRB 251113A: AstroSat CZTI detection
  37. Konus-Wind detection of GRB 251108C
  38. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  39. IPN triangulation of GRB 251108C
  40. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  41. GRB 251111A: SVOM/ECLAIRs refined analysis
  42. GRB 251025B: SVOM/ECLAIRs refined analysis
  43. GRB 251112A: Swift/UVOT Upper Limits
  44. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  45. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  46. Swift Trigger 1413695: a possible GRB 251112A
  47. GRB251111A: 1.3m DFOT optical upper limit
  48. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  49. GRB 251111A: Swift-XRT afterglow detection
  50. GRB 251111A: SVOM/VT optical observations with X-band data
  51. GRB 251111A: SVOM/VT optical observations with VHF data
  52. GRB 251111A: LCO optical observation
  53. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  54. GRB 251111A: SVOM detection of a soft burst
  55. GRB 251106A: Swift/UVOT Upper Limits
  56. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  57. GRB 251105A: AstroSat CZTI detection
  58. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  59. GRB 251102B: SVOM/GRM observation
  60. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  61. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  62. GRB 251106A: Swift-XRT afterglow detection
  63. GRB 251106A: Kilonova-Catcher optical upper limit
  64. Fermi GBM Sub-Threshold Detection of GRB 251106A
  65. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  66. GRB 251106A: MASTER optical observations
  67. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  68. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  69. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  70. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  71. GRB 251103B: Swift/UVOT Upper Limits
  72. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  73. GRB 251105A: Fermi GBM Final Real-time Localization
  74. GRB 251103B: Fermi GBM observation
  75. GRB 251104A: SVOM detection of a burst
  76. GRB 251103A: WFST optical observations
  77. EP251102a: OHP/T193 optical observations
  78. GRB 251103A: OHP/T193 optical observations
  79. GRB 251103A: Xinglong 2.16m optical detection
  80. GRB 251103A: KAIT optical observations
  81. GRB 251103B: Nanshan/HMT optical upper limit
  82. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  83. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  84. GRB 251103B: MITSuME Akeno optical upper limits
  85. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  86. EP251102a: NIR observations with WINTER
  87. GRB 251103A: J-band detection with WINTER
  88. GRB 251103B: GROWTH-India Telescope optical upper limits
  89. GRB 251103A: Kilonova-Catcher optical afterglow detection
  90. GRB 251103B: Enhanced Swift-XRT position
  91. GRB 251103B: Swift detection of a burst
  92. GRB 251103A: Swift/UVOT Detection
  93. GRB 251103A: Swift-XRT afterglow detection
  94. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  95. EP251102a: Einstein Probe detection of a fast X-ray transient
  96. GRB 251025B: OHP/T193 optical upper limit
  97. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  98. GRB 251103A: LCO optical observation
  99. EP251102.890: COLIBRÍ optical counterpart candidate
  100. GRB 251102A: AstroSat CZTI detection

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