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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"

24595 results found.

  1. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  2. GRB 231129A: Swift-BAT refined analysis
  3. GRB 231129A: JinShan optical upper limit
  4. GRB 231129C: Glowbug gamma-ray detection
  5. GRB 231129C: Swift-XRT observations
  6. GRB 231129A: Swift/UVOT Upper Limits
  7. GRB 231129A: optical upper limit in Mondy observatory
  8. GRB 231129C: Fermi GBM Observation of a very bright GRB
  9. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  10. GRB 231129C: MAXI/GSC detection
  11. GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)
  12. GRB 231129C: Fermi GBM detection of a very bright burst
  13. GRB 231129A: Enhanced Swift-XRT position
  14. LIGO/Virgo/KAGRA S231129ac: Updated Sky localization
  15. GRB 231129A: Swift-XRT refined Analysis
  16. Fermi trigger No 722977823: Global MASTER-Net observations report
  17. GRB 231129B: MAXI/GSC detection
  18. Fermi-LAT gamma-ray observations of IceCube-231125A
  19. LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
  20. GRB 231129A: INTEGRAL detection of a long GRB
  21. GRB 231129A: Swift detection of a burst
  22. LIGO/Virgo/KAGRA S231127cg: Updated Sky localization
  23. GRB 231123C: Fermi GBM Observation
  24. GRB 231123B: Fermi GBM Observation
  25. IceCube-231125A: Upper limits from a search for additional neutrino events in IceCube
  26. LIGO/Virgo/KAGRA S231127cg: Identification of a GW compact binary merger candidate
  27. GRB 231117A: MeerKAT 1.3GHz detection
  28. GRB 231127A: AstroSat CZTI detection
  29. GRB 231125A (short): Glowbug gamma-ray detection
  30. GRB 231123B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  31. GRB 231125A: AstroSat CZTI detection of a short burst
  32. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  33. GRB 231123C: Insight-HXMT/HE detection
  34. Fermi trigger No 722460326: Global MASTER-Net observations report
  35. GRB 231123C (short): Glowbug gamma-ray detection
  36. GRB 231124A: Glowbug gamma-ray detection
  37. GRB230728A: VIRT optical upper limit
  38. GRB230506C: VIRT optical upper limit
  39. GRB230506B: VIRT optical upper limit
  40. GRB 231123C: Swift/BAT-GUANO detection of a short burst likely outside the coded FOV
  41. LIGO/Virgo/KAGRA S231118an: Updated Sky localization and EM Bright Classification
  42. GRB 231117A: Mondy optical observations
  43. LIGO/Virgo/KAGRA S231123cg: Identification of a GW compact binary merger candidate
  44. GRB 231118A: REM optical afterglow detection
  45. GRB 231122B: AstroSat CZTI detection
  46. GRB 231122B: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  47. GRB 231122B: Glowbug gamma-ray detection
  48. GRB 231117A: Continued GTC Observations
  49. GRB 231122A: GECAM detection
  50. GRB 231122B: GECAM detection
  51. GRB 231117A: Swift/UVOT late time observations
  52. GRB 231117A: GTC Near-Infrared Observations
  53. GRB 231117A: Swift-BAT refined analysis
  54. LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
  55. LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
  56. LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
  57. LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
  58. LIGO/Virgo/KAGRA S231119u: Updated Sky localization and Source Classification
  59. LIGO/Virgo/KAGRA S231118ab: Updated Sky localization and Source Classification
  60. LIGO/Virgo/KAGRA S231118d: Updated Sky localization and Source Classification
  61. GRB 231118A: VZLUSAT-2 detection
  62. GRB 231117A: AMI-LA radio observations
  63. GRB 231118A: Swift-BAT refined analysis
  64. 231118A: Swift-UVOT Detection
  65. GRB231117A: Swift-UVOT detection
  66. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  67. GRB 231118B: Fermi GBM observation
  68. GRB 231118A: Fermi GBM observation
  69. LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
  70. GRB 231117A: Swift-XRT refined Analysis
  71. GRB 231118A: Swift-XRT refined Analysis
  72. GRB 231118A: MeerLICHT afterglow detection
  73. LIGO/Virgo/KAGRA S231119u: One counterpart neutrino candidate from IceCube neutrino searches
  74. GRB 231117A: OHP/T120 optical observations
  75. GRB 231118A: VLT/X-shooter redshift
  76. Fermi trigger No 722039659: Global MASTER-Net observations report
  77. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
  78. LIGO/Virgo/KAGRA S231119u: Identification of a GW compact binary merger candidate
  79. GRB 231117A: AKO Follow-Up Observation
  80. GRB 231118A: Las Cumbres optical detection
  81. GRB 231118B: BALROG localization (Fermi Trigger 722039659 / GRB 231118940)
  82. GRB 231118A: LCOGT Optical Observations
  83. GRB 231118A: Enhanced Swift-XRT position
  84. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  85. GRB 231118A: Skynet Optical Afterglow Discovery
  86. LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate
  87. GRB 231117A: GRBAlpha detection
  88. LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
  89. GRB 231115A: Wendelstein Optical/Infrared Observations
  90. GRB 231115A: JinShan optical upper limits
  91. LIGO/Virgo/KAGRA S231118d: Identification of a GW compact binary merger candidate
  92. GRB 231117A: GIT optical follow-up
  93. GRB 231117A: LT observations consistent with fading
  94. GRB 231117A: REM optical and NIR early-time observations
  95. GRB 231117A: AKO Optical Upper Limit
  96. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  97. GRB 231117A (short): Glowbug gamma-ray detection
  98. GRB 231117A: ATLAS non-detection of an optical counterpart
  99. GRB 231115A : OHP/T120 optical upper limit
  100. GRB 231117A : MITSuME Akeno optical upper limits

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