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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

20993 results found.

  1. GRB 251013C: Liverpool Telescope observations
  2. GRB 251013C: Leavitt Observatory optical photometry
  3. Fermi GRB 251016B: Global MASTER-Net observations report
  4. GRB 251017A: JinShan observations of the optical afterglow
  5. Swift GRB 251017A: Global MASTER-Net observations report
  6. GRB 251017A: COLIBRÍ Early Afterglow Detection
  7. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  8. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) observations of a strong and late rebrightening of the optical counterpart
  9. GRB 251013C: VLA detection
  10. sb25101602: Swift-XRT counterpart detection
  11. Fermi GRB 251016A: Global MASTER-Net observations report
  12. GRB 251014A: Swift-XRT observations
  13. GRB 251014B: PRIME J-band upper limit
  14. IceCube Alert 251014.77: Global MASTER-Net observations report
  15. Swift GRB251015.60: Global MASTER-Net observations report
  16. GRB 251013C: Kilonova-Catcher optical afterglow detection
  17. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  18. GRB 251013D: Swift/UVOT Observations
  19. GRB 251013C: Swift/UVOT Detection
  20. GRB 251013C: detection of a radio counterpart at 15.5GHz
  21. GRB 251013C: SVOM/ECLAIRs refined analysis
  22. GRB 251013D: Swift-XRT observations
  23. GRB 251014B: Swift-XRT observations
  24. GRB 251014B: Swift/UVOT Upper Limits
  25. GRB 251014B: VLT/FORS2 Optical Observation
  26. GRB 251014D: Swift/UVOT Upper Limits
  27. GRB 251014D: Swift-XRT afterglow detection
  28. GRB 251013C: MAO/AZT-22 optical observations
  29. GRB 251013C: Swift ToO observations
  30. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) further multi-band optical observations
  31. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  32. GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  33. GRB 251014A: PRIME near-infrared upper limits
  34. GRB 251014A: VLT/FORS2 Optical Observation
  35. GRB 251013C: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an bright optical counterpart
  36. GRB 251013C: MarSEC, optical afterglow photometry
  37. GRB 251014B: Swift ToO observations
  38. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  39. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  40. GRB 251013C: Bassano Bresciano Observatory optical observations
  41. GRB 251013C: Early and late-time optical counterpart detection by LCO
  42. LIGO/Virgo/KAGRA S251014cn: NED Galaxies in the 3-Initial Localization Volume
  43. GRB 251013D: Swift ToO observations
  44. GRB 251014A: DDOTI Upper Limit
  45. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  46. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  47. GRB 251013C: Asiago optical observations
  48. GRB 251013C: ABObservatory optical observations
  49. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  50. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  51. GRB 251013C: ALMA detection
  52. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  53. GRB 251013C: DDOTI detection of the optical afterglow
  54. GRB 251013C: SLKT optical afterglow photometry
  55. Swift GRB 251014A: Global MASTER-Net observations report
  56. Fermi trigger No 782044789: Global MASTER-Net observations report
  57. Fermi GRB 251013C: Global MASTER-Net observations report
  58. Fermi GRB 251013B: Global MASTER-Net observations report
  59. Fermi GRB 251013D: Global MASTER-Net observations report
  60. GRB 251013C: Swift-XRT counterpart detection
  61. GRB 251013C: GOTO optical afterglow detection
  62. GRB 251013C: SAO RAS optical observations
  63. GRB 251013C: LCO optical afterglow detection
  64. GRB 251013C: Optical Observations via Virtual Telescope Project, Italy
  65. GRB 251013C: LAST detection of optical counterpart
  66. GRB 251003A: Mondy optical upper limit
  67. Fermi GRB 251013A: Global MASTER-Net observations report
  68. GRB 251011B inspection: MASTER orphan GRB detection
  69. GRB 251011B: Swift/UVOT Upper Limits
  70. Fermi GRB 251011A: Global MASTER-Net observations report
  71. GRB 251011B : MASTER optical observations
  72. GRB 251007B: Swift/UVOT Upper Limits
  73. GRB251007A: Swift/UVOT Detection
  74. GRB 251007B - SVOM/ECLAIRs refined analysis
  75. EP251006a: Global MASTER-Net observations report
  76. GRB 251002A - SVOM/ECLAIRs refined analysis
  77. IceCube Alert 251008A: Global MASTER-Net observations report
  78. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  79. GRB 251007B: SVOM/VT optical candidate
  80. GRB 251007A: NOT optical observations
  81. GRB 251007A: SVOM/C-GFT optical observations
  82. GRB 251005C: PRIME J-band upper limit
  83. Swift GRB 251007B: Global MASTER-Net observations report
  84. GRB 251007B: SVOM/C-GFT upper limit
  85. Swift GRB 251007A: Global MASTER-Net observations report
  86. GRB 251007B: SVOM detection of a faint burst
  87. GRB 251007B: Swift detection of a burst
  88. GRB 250702B/EP250702a: JWST/NIRCam Observations
  89. GRB 251006B/EP251006a: SVOM/VT optical candidate
  90. Fermi GRB 251006B: Global MASTER-Net observations report
  91. GRB 251005C: COLIBRÍ optical observations
  92. Fermi GRB 251006A: Global MASTER-Net observations report
  93. GRB 251005C: VLT/X-shooter Imaging
  94. GRB 251003A: LAST optical observations
  95. GRB 251002A: LAST optical observations
  96. GRB 251005C: Swift/UVOT Upper Limits
  97. Swift GRB 251005A: Global MASTER-Net observations report
  98. GRB 251005C: GOTO optical upper limits
  99. Fermi trigger No 781367244: Global MASTER-Net observations report
  100. GRB 251002A: Mondy/AZT-33IK optical observations

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