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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"

19577 results found.

  1. EP251023a: Assy AZT-20 optical observations
  2. EP251023a: UAFO and AbAO optical observations
  3. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  4. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  5. GRB 251025B: further Mondy optical observations
  6. GRB 251111A: Mondy optical upper limit
  7. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  8. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  9. GRB 251116B: LCO optical upper limits
  10. GRB 251116C: LCO optical upper limits
  11. GRB 251116B: SVOM detection of a burst
  12. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  13. GRB 251115A: Tiled Swift observations
  14. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  15. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  16. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  17. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  18. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  19. GRB 251112A: Swift/UVOT Upper Limits
  20. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  21. Swift Trigger 1413695: a possible GRB 251112A
  22. GRB251111A: 1.3m DFOT optical upper limit
  23. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  24. GRB 251111A: Swift-XRT afterglow detection
  25. GRB 251111A: SVOM/VT optical observations with X-band data
  26. GRB 251111A: SVOM/VT optical observations with VHF data
  27. GRB 251111A: LCO optical observation
  28. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  29. GRB 251106A: Swift/UVOT Upper Limits
  30. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  31. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  32. GRB 251102B: SVOM/GRM observation
  33. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  34. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  35. GRB 251106A: Swift-XRT afterglow detection
  36. GRB 251106A: Kilonova-Catcher optical upper limit
  37. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  38. GRB 251106A: MASTER optical observations
  39. GRB 251106A: SVOM detection of a burst
  40. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  41. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  42. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  43. GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
  44. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  45. GRB 251103B: Swift/UVOT Upper Limits
  46. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  47. GRB 251104A: SVOM detection of a burst
  48. GRB 251103A: WFST optical observations
  49. GRB 251103A: Xinglong 2.16m optical detection
  50. GRB 251103A: KAIT optical observations
  51. GRB 251103B: Nanshan/HMT optical upper limit
  52. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  53. GRB 251103B: MITSuME Akeno optical upper limits
  54. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  55. EP251102a: NIR observations with WINTER
  56. GRB 251103A: J-band detection with WINTER
  57. Swift GRB 251103B: Global MASTER-Net observations report
  58. GRB 251103B: GROWTH-India Telescope optical upper limits
  59. GRB 251103A: Kilonova-Catcher optical afterglow detection
  60. GRB 251103B: Enhanced Swift-XRT position
  61. GRB 251103B: Swift detection of a burst
  62. GRB 251103A: Swift/UVOT Detection
  63. GRB 251103A: Swift-XRT afterglow detection
  64. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  65. EP251102a: Einstein Probe detection of a fast X-ray transient
  66. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  67. GRB 251103A: LCO optical observation
  68. EP251102.890: COLIBRÍ optical counterpart candidate
  69. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  70. GRB 251103A: LCO optical afterglow detection
  71. GRB 251103A: NOT optical afterglow candidate
  72. GRB 251103A: SVOM detection of a bright burst
  73. GRB 251031A: Fermi GBM Observation
  74. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  75. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  76. GRB 251025C: SVOM/GRM observation
  77. GRB 251028A: SVOM/GRM observation
  78. GRB 251022A: Swift-XRT confirmation of fading
  79. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  80. GRB 251028B: Fermi/GBM observation
  81. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  82. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  83. GRB251026B: PRIME H-band upper limit
  84. GRB251025B: 3.6m DOT Optical Observations
  85. SVOM trigger sb25102702/GRB 251027A is not a GRB
  86. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  87. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  88. EP251027.145: COLIBRÍ optical upper limits
  89. GRB 251022A: SVOM/GRM observation
  90. GRB 251026B: Swift ToO observations
  91. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  92. GRB 251027A: LCO optical upper limit
  93. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  94. GRB 251023B / EP251023b: Mondy optical upper limit
  95. GRB 251017A: INASAN-Kislovodsk optical observations
  96. GRB 251026A: Mondy optical upper limit
  97. GRB 251025B: Mondy optical observations
  98. GRB 251025B: Kilonova-Catcher optical afterglow detection
  99. GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
  100. GRB 251026B: Tentative GOTO optical counterpart candidate

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