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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').

22420 results found.

  1. EP240626a: EP-WXT detection of a fast X-ray transient
  2. EP240625a: NOT optical counterpart candidate
  3. EP240625a: EP-FXT detection of the X-ray emission
  4. EP240625a: EP-WXT detection of a fast X-ray transient
  5. GRB240624A: Fermi GBM Observation
  6. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  7. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  8. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  9. GRB240615A: Gemini-North observations of the BAT and XRT positions
  10. GRB240615A: Gemini-North observations of the BAT and XRT positions
  11. GRB 240619A: detection of a radio counterpart with AMI-LA
  12. GRB 240624A: Swift detection of a burst
  13. GRB 240619A: J-band detection with WINTER
  14. LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification
  15. EP240618a: NOT optical counterpart candidate
  16. LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification
  17. GRB 240529A: JinShan optical observations
  18. LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification
  19. LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification
  20. EP240618a: GSP optical upper limit
  21. LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate
  22. LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  24. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  25. GRB 240619C: NuSTAR automated detection of the GRB
  26. GRB 240619A: Fermi GBM Observation
  27. Fermi GBM Sub-Threshold Detection of GRB 240619C
  28. GRB 240615A: NOT optical observations
  29. GRB 240619C: AstroSat CZTI detection
  30. EP240618a: TRT optical upper limit
  31. EP240617a: STEP/T80S optical limits
  32. GRB 240615A: possible transient detection from Wendelstein observations
  33. LIGO/Virgo/KAGRA S240615dg: Updated Sky localization
  34. LIGO/Virgo/KAGRA S240618ah: Updated Sky localization
  35. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  36. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  37. GRB240615A: 1.3m DFOT optical upper limit
  38. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  39. EP240617a: EP-WXT detection of a fast X-ray transient
  40. EP240618a: EP-WXT detection of a fast X-ray transient and EP-FXT quick follow-up
  41. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  42. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  43. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  44. GRB 240615A: J-band upper limits from WINTER
  45. LIGO/Virgo/KAGRA S240615ea: Updated Sky localization
  46. GRB 240615A: Swift-XRT observations
  47. X-ray transient EP240414a: Chandra late time observation
  48. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  49. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  51. GRB 240603A: VZLUSAT-2 detection
  52. EXO 0748-676: Swift-BAT refined analysis
  53. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  54. GRB 240529A: LBT optical detection and late temporal decay
  55. GRB 240529A : MITSuME Akeno optical afterglow detection
  56. Trigger 1236151: Swift detection of EXO 0748-676
  57. IPN triangulation of GRB 240607A
  58. Fermi trigger No 739632045: Global MASTER-Net observations report
  59. GRB 240607A: Fermi GBM Observation
  60. GRB 240606B: Fermi GBM Observation
  61. Swift Trigger 1235109: consistent with noise and not astrophysical
  62. GRB 240607A: Fermi GBM detection of a very bright burst
  63. GRB 240529A: radio detection with AMI-LA
  64. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  65. GRB 240606B: Swift-XRT afterglow detection
  66. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  67. Swift Trigger 1235109: a possible GRB 240606A
  68. LIGO/Virgo/KAGRA S240601co: Updated Sky localization
  69. GRB 240604A: GECAM detection of a long burst
  70. GRB 240529A: SAO RAS optical observations
  71. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  72. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  73. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  74. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  75. Swift Trigger 1232465: consistent with noise
  76. GRB 240529A: MASTER prompt OT detection
  77. GRB 240603A: GECAM detection of a short burst
  78. GRB 240529A: continued SAO RAS optical observations
  79. GRB 240529A: OSN optical detection
  80. The EP-WXT source triggered on June 1st is likely a flaring star
  81. GRB 240529A: further SAO RAS optical observations
  82. LIGO/Virgo/KAGRA S240601aj: Updated Sky localization
  83. LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate
  84. Swift Trigger 1232465 is not a GRB
  85. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  86. LIGO/Virgo/KAGRA S240530a: Updated Sky localization
  87. LXT 240528A: GSP optical upper limit
  88. GRB 240529A: 1.3m DFOT Optical observations
  89. LIGO/Virgo/KAGRA S240527en: Updated Sky localization
  90. LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate
  91. GRB 240531A: AstroSat CZTI detection of a short burst
  92. GRB 240529A : Mondy optical observations
  93. GRB 240529A: SAO RAS optical observations
  94. LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
  95. LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate
  96. GRB 240529A: GROWTH-India optical follow-up
  97. GRB 240529A: T193/MISTRAL observations
  98. GRB 240529A: Redshift from GTC/OSIRIS+
  99. GRB 240529A: AKO Optical Afterglow Detection
  100. LIGO/Virgo/KAGRA S240530a: Identification of a GW compact binary merger candidate

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