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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"

19089 results found.

  1. EP251118a: VLT near-infrared observation
  2. GRB 251116D: SVOM/GRM observation of a long GRB
  3. GRB 251119A: SVOM detection of a possible burst
  4. EP251118a: NOT candidate optical counterpart
  5. GRB 251118A: Swift ToO observations
  6. EP251118a: Einstein Probe detected of a fast X-ray transient
  7. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  8. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  9. GRB 251117A: SVOM/GRM observation of a short burst
  10. GRB 251117A: Tiled Swift observations
  11. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  13. EP251023a: Assy AZT-20 optical observations
  14. EP251023a: UAFO and AbAO optical observations
  15. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  16. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  17. GRB 251025B: further Mondy optical observations
  18. GRB 251111A: Mondy optical upper limit
  19. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  20. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  21. GRB 251116B: LCO optical upper limits
  22. GRB 251116C: LCO optical upper limits
  23. GRB 251116B: SVOM detection of a burst
  24. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  25. GRB 251115A: Tiled Swift observations
  26. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  27. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  28. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  29. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  30. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  31. GRB 251112A: Swift/UVOT Upper Limits
  32. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  33. Swift Trigger 1413695: a possible GRB 251112A
  34. GRB251111A: 1.3m DFOT optical upper limit
  35. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  36. GRB 251111A: Swift-XRT afterglow detection
  37. GRB 251111A: SVOM/VT optical observations with X-band data
  38. GRB 251111A: SVOM/VT optical observations with VHF data
  39. GRB 251111A: LCO optical observation
  40. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  41. GRB 251106A: Swift/UVOT Upper Limits
  42. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  43. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  44. GRB 251102B: SVOM/GRM observation
  45. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  46. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  47. GRB 251106A: Swift-XRT afterglow detection
  48. GRB 251106A: Kilonova-Catcher optical upper limit
  49. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  50. GRB 251106A: MASTER optical observations
  51. GRB 251106A: SVOM detection of a burst
  52. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  53. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  54. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  55. GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
  56. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  57. GRB 251103B: Swift/UVOT Upper Limits
  58. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  59. GRB 251104A: SVOM detection of a burst
  60. GRB 251103A: WFST optical observations
  61. GRB 251103A: Xinglong 2.16m optical detection
  62. GRB 251103A: KAIT optical observations
  63. GRB 251103B: Nanshan/HMT optical upper limit
  64. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  65. GRB 251103B: MITSuME Akeno optical upper limits
  66. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  67. EP251102a: NIR observations with WINTER
  68. GRB 251103A: J-band detection with WINTER
  69. Swift GRB 251103B: Global MASTER-Net observations report
  70. GRB 251103B: GROWTH-India Telescope optical upper limits
  71. GRB 251103A: Kilonova-Catcher optical afterglow detection
  72. GRB 251103B: Enhanced Swift-XRT position
  73. GRB 251103B: Swift detection of a burst
  74. GRB 251103A: Swift/UVOT Detection
  75. GRB 251103A: Swift-XRT afterglow detection
  76. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  77. EP251102a: Einstein Probe detection of a fast X-ray transient
  78. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  79. GRB 251103A: LCO optical observation
  80. EP251102.890: COLIBRÍ optical counterpart candidate
  81. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  82. GRB 251103A: LCO optical afterglow detection
  83. GRB 251103A: NOT optical afterglow candidate
  84. GRB 251103A: SVOM detection of a bright burst
  85. GRB 251031A: Fermi GBM Observation
  86. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  87. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  88. GRB 251025C: SVOM/GRM observation
  89. GRB 251028A: SVOM/GRM observation
  90. GRB 251022A: Swift-XRT confirmation of fading
  91. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  92. GRB 251028B: Fermi/GBM observation
  93. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  94. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  95. GRB251026B: PRIME H-band upper limit
  96. GRB251025B: 3.6m DOT Optical Observations
  97. SVOM trigger sb25102702/GRB 251027A is not a GRB
  98. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  99. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  100. EP251027.145: COLIBRÍ optical upper limits

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