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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').

22377 results found.

  1. GRB 240615A: J-band upper limits from WINTER
  2. LIGO/Virgo/KAGRA S240615ea: Updated Sky localization
  3. GRB 240615A: Swift-XRT observations
  4. X-ray transient EP240414a: Chandra late time observation
  5. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  6. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  7. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  8. GRB 240603A: VZLUSAT-2 detection
  9. EXO 0748-676: Swift-BAT refined analysis
  10. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  11. GRB 240529A: LBT optical detection and late temporal decay
  12. GRB 240529A : MITSuME Akeno optical afterglow detection
  13. Trigger 1236151: Swift detection of EXO 0748-676
  14. IPN triangulation of GRB 240607A
  15. Fermi trigger No 739632045: Global MASTER-Net observations report
  16. GRB 240607A: Fermi GBM Observation
  17. GRB 240606B: Fermi GBM Observation
  18. Swift Trigger 1235109: consistent with noise and not astrophysical
  19. GRB 240607A: Fermi GBM detection of a very bright burst
  20. GRB 240529A: radio detection with AMI-LA
  21. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  22. GRB 240606B: Swift-XRT afterglow detection
  23. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  24. Swift Trigger 1235109: a possible GRB 240606A
  25. LIGO/Virgo/KAGRA S240601co: Updated Sky localization
  26. GRB 240604A: GECAM detection of a long burst
  27. GRB 240529A: SAO RAS optical observations
  28. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  29. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  30. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  31. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  32. Swift Trigger 1232465: consistent with noise
  33. GRB 240529A: MASTER prompt OT detection
  34. GRB 240603A: GECAM detection of a short burst
  35. GRB 240529A: continued SAO RAS optical observations
  36. GRB 240529A: OSN optical detection
  37. The EP-WXT source triggered on June 1st is likely a flaring star
  38. GRB 240529A: further SAO RAS optical observations
  39. LIGO/Virgo/KAGRA S240601aj: Updated Sky localization
  40. LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate
  41. Swift Trigger 1232465 is not a GRB
  42. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  43. LIGO/Virgo/KAGRA S240530a: Updated Sky localization
  44. LXT 240528A: GSP optical upper limit
  45. GRB 240529A: 1.3m DFOT Optical observations
  46. LIGO/Virgo/KAGRA S240527en: Updated Sky localization
  47. LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate
  48. GRB 240531A: AstroSat CZTI detection of a short burst
  49. GRB 240529A : Mondy optical observations
  50. GRB 240529A: SAO RAS optical observations
  51. LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
  52. LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate
  53. GRB 240529A: GROWTH-India optical follow-up
  54. GRB 240529A: T193/MISTRAL observations
  55. GRB 240529A: Redshift from GTC/OSIRIS+
  56. GRB 240529A: AKO Optical Afterglow Detection
  57. LIGO/Virgo/KAGRA S240530a: Identification of a GW compact binary merger candidate
  58. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  59. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  60. GRB 240529A: J-band detections with WINTER
  61. GRB 240529A: Skynet Optical Observations
  62. LXT 240528A: LEIA detection of a fast X-ray transient
  63. GRB 240529A: Swift-BAT refined analysis
  64. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  65. GRB 240529A: Swift-XRT refined Analysis
  66. GRB 240529A: Swift/UVOT Detection
  67. GRB 240529A: NOT optical observations
  68. GRB 240527B: Swift-XRT afterglow detection
  69. GRB 240529A: Enhanced Swift-XRT position
  70. GRB 240529A: Swift detection of a burst with an optical counterpart
  71. LIGO/Virgo/KAGRA S240527fv: Updated Sky localization
  72. GRB 240527B: Fermi GBM Observation
  73. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  75. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  76. GRB 240523A: Swift-BAT refined analysis
  77. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  78. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  79. GRB 240523A: Swift-XRT refined Analysis
  80. GRB 240523A: Enhanced Swift-XRT position
  81. GRB 240523A: Swift detection of a burst
  82. GRB 240521B: Fermi GBM Observation
  83. Fermi GBM Sub-Threshold Detection of GRB 240516B
  84. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  85. LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification
  86. EP240518a: GSP optical upper limit
  87. GRB 240521A: GECAM-B detection of a long burst
  88. GRB 240516B: AstroSat CZTI detection
  89. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  90. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  91. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  92. LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
  93. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  94. GRB 240514B: VZLUSAT-2 detection
  95. GRB 240504A: VZLUSAT-2 detection
  96. GRB 240502A: VZLUSAT-2 detection
  97. GRB 240516A: Swift/UVOT Upper Limits
  98. EP240518a: possibly identified with a flare star by EP-FXT
  99. GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
  100. EP240518a: EP-WXT detection of a new X-ray transient

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