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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').
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"

45645 results found.

  1. GRB 251013C: MarSEC, optical afterglow photometry
  2. GRB 251013C: OHP/T193 optical afterglow photometry and spectroscopy
  3. GRB 251014B: Swift ToO observations
  4. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  5. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  6. GRB 251013C: Bassano Bresciano Observatory optical observations
  7. GRB 251013C: Early and late-time optical counterpart detection by LCO
  8. LIGO/Virgo/KAGRA S251014cn: NED Galaxies in the 3-Initial Localization Volume
  9. GRB 251013C: Fermi GBM Observation
  10. GRB 251013D: Swift ToO observations
  11. GRB 251014A: DDOTI Upper Limit
  12. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  13. LIGO/Virgo/KAGRA S251014cn: Identification of a GW compact binary merger candidate
  14. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  15. GRB 251013C: Asiago optical observations
  16. GRB 251013A: CALET Gamma-Ray Burst Monitor detection
  17. GRB 251013C: ABObservatory optical observations
  18. GRB 251014A: SAO RAS optical upper limit
  19. GRB 251014A: Fermi GBM Observation
  20. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  21. GRB 251013C: EP-FXT counterpart detection
  22. GRB 251013C: AstroSat CZTI detection
  23. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  24. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  25. GRB 251013C: ALMA detection
  26. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  27. GRB 251013C: DDOTI detection of the optical afterglow
  28. GRB 251013C: SLKT optical afterglow photometry
  29. Swift GRB 251014A: Global MASTER-Net observations report
  30. GRB 251014A: Swift detection of a possibly-short burst
  31. GRB 251014A: Fermi GBM Final Real-time Localization
  32. Fermi trigger No 782044789: Global MASTER-Net observations report
  33. Fermi GRB 251013C: Global MASTER-Net observations report
  34. Fermi GRB 251013B: Global MASTER-Net observations report
  35. Fermi GRB 251013D: Global MASTER-Net observations report
  36. GRB 251013C: Swift-XRT counterpart detection
  37. GRB 251013C: GOTO optical afterglow detection
  38. GRB 251013C: SAO RAS optical observations
  39. GRB 251013C: LCO optical afterglow detection
  40. GRB 251013C: Optical Observations via Virtual Telescope Project, Italy
  41. GRB 251013C: NOT spectroscopic redshift z = 0.572
  42. GRB 251013C: LAST detection of optical counterpart
  43. GRB 251013C: BOOTES-6 early optical detection
  44. GRB 251013D: Fermi GBM Final Real-time Localization
  45. GRB 251013C: SVOM/VT optical observation
  46. GRB 251013C: SVOM detection of a burst
  47. GRB 251013C: Fermi GBM Final Real-time Localization
  48. LIGO/Virgo/KAGRA S251013x: Updated Sky localization and Source Classification
  49. GRB 251013B: SVOM/GRM observation
  50. GRB 251013A: SVOM/GRM observation
  51. GRB 251003A: Mondy optical upper limit
  52. MASTER OT J011025.98-583210.6 : SVOM/VT optical observation
  53. GRB 251013B: Fermi GBM Final Real-time Localization
  54. Fermi GRB 251013A: Global MASTER-Net observations report
  55. GRB 251013A: Fermi GBM Final Real-time Localization
  56. LIGO/Virgo/KAGRA S251013x: Identification of a GW compact binary merger candidate
  57. GRB 251011B inspection: MASTER orphan GRB detection
  58. GRB 251011A: Insight-HXMT detection
  59. GRB 251011B: Swift/UVOT Upper Limits
  60. Fermi GRB 251011A: Global MASTER-Net observations report
  61. GRB 251012A: Fermi GBM Final Real-time Localization
  62. GRB 251011B: SVOM/GRM observation
  63. GRB 251011B: Swift-XRT refined Analysis
  64. GRB 251011B: Fermi GBM Observation
  65. GRB 251011B : MASTER optical observations
  66. GRB 251011C: Fermi GBM Final Real-time Localization
  67. GRB 251011B: Enhanced Swift-XRT position
  68. GRB 251010A: AstroSat CZTI detection
  69. GRB 251011A: AstroSat CZTI detection
  70. GRB 251009B: SVOM/GRM observation of short GRB
  71. GRB 251011B: Swift detection of a burst
  72. GRB 251011B: Fermi GBM Final Real-time Localization
  73. GRB 251011A: Fermi GBM Final Real-time Localization
  74. Fermi Gamma-ray Burst Monitor trigger 781824269/251010892 is not a GRB
  75. GRB 251007B: Swift/UVOT Upper Limits
  76. GRB 251010A: Fermi GBM Final Real-time Localization
  77. GRB251007A: Swift/UVOT Detection
  78. GRB 251009A: GECAM-B detection of a short burst
  79. GRB 251009A: Insight-HXMT detection of a short burst
  80. GRB 251009B (short): Glowbug gamma-ray detection
  81. GRB 251009B: Insight-HXMT detection of a short burst
  82. GRB 251007A: Swift-BAT refined analysis
  83. GRB 251009A: SVOM/GRM observation of short GRB with possible tail emission
  84. GRB 251007A: SVOM/GRM observation
  85. GRB 251007A: Insight-HXMT detection
  86. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  87. GRB 251007B - SVOM/ECLAIRs refined analysis
  88. SVOM/sb25101004: SVOM detection of a stellar flare
  89. GRB 251009A: Fermi GBM Final Localization
  90. GRB 250916A: TERI Gamma-ray detection
  91. GRB 250919A: TERI gamma-ray detection
  92. EP251006a: Global MASTER-Net observations report
  93. GRB 251006A: Fermi GBM Observation
  94. GRB 251007A: 1.5m OSN and 2.2m CAHA optical follow-up
  95. GRB 251002A - SVOM/ECLAIRs refined analysis
  96. IceCube alert 141456_888784 retraction
  97. IceCube Alert 251008A: Global MASTER-Net observations report
  98. GRB 251003A: Fermi GBM Observation
  99. GRB 251006B: Fermi GBM Observation
  100. GRB 251007B: COLIBRÍ optical upper limit

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