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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"

28114 results found.

  1. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  2. GRB 251016A: AstroSat CZTI detection of a short burst
  3. GRB 251017A: Enhanced Swift-XRT position
  4. GRB 251017A: COLIBRÍ Early Afterglow Detection
  5. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  6. GRB 251017A: Swift detection of a burst with an optical counterpart
  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 251007B: Swift-BAT refined analysis
  10. GRB 251014D: Swift-BAT refined analysis
  11. GRB 251016A: BOOTES-6/DPRT optical upper limit
  12. GRB 251016A: Glowbug gamma-ray detection of a short burst
  13. sb25101602: Swift-XRT counterpart detection
  14. GRB 251014A: Swift-XRT observations
  15. LIGO/Virgo/KAGRA S251014cn: Updated Sky localization
  16. GRB 251014B: PRIME J-band upper limit
  17. Upper limits from a search for additional neutrino events in IceCube
  18. IceCube Alert 251014.77: Global MASTER-Net observations report
  19. GRB 251013C: Kilonova-Catcher optical afterglow detection
  20. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  21. GRB 251013D: Swift/UVOT Observations
  22. GRB 251013C: Swift/UVOT Detection
  23. GRB 251013C: detection of a radio counterpart at 15.5GHz
  24. GRB 251013D: Swift-XRT observations
  25. Swift Trigger 1404295: possible GRB 251015A
  26. GRB 251014B: Swift-XRT observations
  27. GRB 251014B: Swift/UVOT Upper Limits
  28. GRB 251014B: VLT/FORS2 Optical Observation
  29. GRB 251014D: Swift/UVOT Upper Limits
  30. GRB 251014D: Swift-XRT afterglow detection
  31. GRB 251013C: MAO/AZT-22 optical observations
  32. GRB 251011B: SVOM/VT optical upper limit
  33. GRB 251013D: Fermi GBM Observation
  34. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) further multi-band optical observations
  35. GRB 251014A: Swift-BAT refined analysis
  36. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  37. GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  38. GRB 251014D: Swift detection of a burst
  39. GRB 251014A: PRIME near-infrared upper limits
  40. GRB 251014A: Glowbug gamma-ray detection of a likely short burst
  41. GRB 251014A: VLT/FORS2 Optical Observation
  42. GRB 251012A: Glowbug gamma-ray detection of a likely short burst
  43. GRB 251013C: MarSEC, optical afterglow photometry
  44. GRB 251013C: OHP/T193 optical afterglow photometry and spectroscopy
  45. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  46. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  47. GRB 251013C: Bassano Bresciano Observatory optical observations
  48. GRB 251013C: Early and late-time optical counterpart detection by LCO
  49. LIGO/Virgo/KAGRA S251014cn: NED Galaxies in the 3-Initial Localization Volume
  50. GRB 251013C: Fermi GBM Observation
  51. GRB 251014A: DDOTI Upper Limit
  52. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  53. LIGO/Virgo/KAGRA S251014cn: Identification of a GW compact binary merger candidate
  54. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  55. GRB 251013C: Asiago optical observations
  56. GRB 251013C: ABObservatory optical observations
  57. GRB 251014A: SAO RAS optical upper limit
  58. GRB 251014A: Fermi GBM Observation
  59. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  60. GRB 251013C: EP-FXT counterpart detection
  61. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  62. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  63. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  64. GRB 251013C: DDOTI detection of the optical afterglow
  65. GRB 251013C: Swift-XRT counterpart detection
  66. GRB 251013C: SAO RAS optical observations
  67. GRB 251013C: LCO optical afterglow detection
  68. GRB 251013C: Optical Observations via Virtual Telescope Project, Italy
  69. GRB 251013C: LAST detection of optical counterpart
  70. GRB 251013C: SVOM/VT optical observation
  71. GRB 251013C: SVOM detection of a burst
  72. LIGO/Virgo/KAGRA S251013x: Updated Sky localization and Source Classification
  73. GRB 251013B: SVOM/GRM observation
  74. GRB 251013A: SVOM/GRM observation
  75. GRB 251003A: Mondy optical upper limit
  76. MASTER OT J011025.98-583210.6 : SVOM/VT optical observation
  77. LIGO/Virgo/KAGRA S251013x: Identification of a GW compact binary merger candidate
  78. GRB 251011B inspection: MASTER orphan GRB detection
  79. GRB 251011B: Swift/UVOT Upper Limits
  80. Fermi GRB 251011A: Global MASTER-Net observations report
  81. GRB 251011B: SVOM/GRM observation
  82. GRB 251011B: Swift-XRT refined Analysis
  83. GRB 251011B: Fermi GBM Observation
  84. GRB 251011B : MASTER optical observations
  85. GRB 251011B: Enhanced Swift-XRT position
  86. GRB 251011B: Swift detection of a burst
  87. GRB 251007B: Swift/UVOT Upper Limits
  88. GRB251007A: Swift/UVOT Detection
  89. GRB 251009A: GECAM-B detection of a short burst
  90. GRB 251009B (short): Glowbug gamma-ray detection
  91. GRB 251007A: Swift-BAT refined analysis
  92. GRB 251007A: SVOM/GRM observation
  93. SVOM/sb25101004: SVOM detection of a stellar flare
  94. GRB 250916A: TERI Gamma-ray detection
  95. GRB 250919A: TERI gamma-ray detection
  96. EP251006a: Global MASTER-Net observations report
  97. GRB 251006A: Fermi GBM Observation
  98. GRB 251003A: Fermi GBM Observation
  99. GRB 251006B: Fermi GBM Observation
  100. GRB 251007B: COLIBRÍ optical upper limit

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