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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').

22274 results found.

  1. GRB 240516A: Fermi GBM Observation
  2. GRB 240511A: Observations from GTC/OSIRIS+
  3. GRB 240516A: Swift detection of a burst
  4. GRB 240511A: radio detection of afterglow candidate
  5. MAXI GRB240514.78: Global MASTER-Net observations report
  6. GRB 240514E: MAXI/GSC detection of a probable afterglow
  7. LIGO/Virgo/KAGRA S240514x: Updated Sky localization
  8. LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate
  9. GRB 240513A: Fermi GBM observation
  10. GRB 240513A: Swift-XRT observations
  11. LIGO/Virgo/KAGRA S240513ei: Updated Sky localization
  12. LIGO/Virgo/KAGRA S240514x: Identification of a GW compact binary merger candidate
  13. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  14. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  15. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  16. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  17. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  18. LIGO/Virgo/KAGRA S240513ei: Identification of a GW compact binary merger candidate
  19. GRB 240511A: Fermi GBM Observation
  20. GRB 240511A: Swift-BAT refined analysis
  21. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  22. GRB 240511A: J-band observations with WINTER
  23. Fermi trigger No 737247400: Global MASTER-Net observations report
  24. Fermi trigger No 737168073: Global MASTER-Net observations report
  25. GRB 240511A: Enhanced Swift-XRT position
  26. GRB 240511A : MITSuME Akeno optical upper limits
  27. LIGO/Virgo/KAGRA S240512r: Updated Sky localization and EM Bright Classification
  28. GRB 240511A: Swift-XRT refined Analysis
  29. LIGO/Virgo/KAGRA S240512r: Identification of a GW compact binary merger candidate
  30. GRB 240511A: Swift detection of a burst
  31. LIGO/Virgo/KAGRA S240511i: Updated Sky localization
  32. Fermi trigger No 737111207: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S240511i: Identification of a GW compact binary merger candidate
  34. LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
  35. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  36. LIGO/Virgo/KAGRA S240422ed: Candidates from the latest GW-MMADS DECam Observations
  37. EP240506a: Xinglong optical upper limit
  38. GRB 240504A: Fermi GBM Observation
  39. EP240506a: Archival radio searching
  40. EP240506a: TRT optical upper limit
  41. LIGO/Virgo/KAGRA S240507p: Updated Sky localization and EM Bright Classification
  42. LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search
  43. EP240506a: Optical upper limit with Kinder observations
  44. IPN triangulation of GRB 240504A
  45. GRB 240502A: 1.3m DFOT Optical upper limit
  46. EP240506a: EP-WXT detection of a new fast X-ray transient
  47. LIGO/Virgo/KAGRA S240507p: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  49. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  50. LIGO/Virgo/KAGRA S240505av: Updated Sky localization and EM Bright Classification
  51. LIGO/Virgo/KAGRA S240505av: Identification of a GW compact binary merger candidate
  52. Fermi trigger No 736461232: Global MASTER-Net observations report
  53. GW170817: VLA observations at ~5.5 yrs since merger
  54. GRB 240504A: BALROG localization (Fermi Trigger 736492377 / GRB 240504217)
  55. GRB 240502A: Fermi GBM Observation
  56. GRB 240415A 1.3m DFOT Optical upper limit
  57. LIGO/Virgo/KAGRA S240501an: Updated Sky localization and EM Bright Classification
  58. LIGO/Virgo/KAGRA S240430ca: Updated Sky localization and EM Bright Classification
  59. GRB 240426A: VZLUSAT-2 detection
  60. GRB 240425A: VZLUSAT-2 detection
  61. MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
  62. GRB 240501B: AstroSat CZTI detection
  63. GRB 240501A: Fermi GBM Final Real-time Localization
  64. GRB 240408B: VZLUSAT-2 detection
  65. GRB 240407A: VZLUSAT-2 detection
  66. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S240430ca: Updated Sky localization and EM Bright Classification
  68. LIGO/Virgo/KAGRA S240430ca: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  70. Additional DECam GW-MMADS Candidates from three nights of observations
  71. Fermi-LAT gamma-ray observations of IceCube-240424A
  72. LIGO/Virgo/KAGRA S240426s: Updated Sky localization
  73. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  74. LIGO/Virgo/KAGRA S240426dl: Updated Sky localization
  75. LIGO/Virgo/KAGRA S240428dr: Updated Sky localization
  76. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
  77. LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a
  79. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  80. EP240426b: AST3-2 optical upper limit
  81. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  82. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  83. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  84. EP240426b: EP-WXT detection of a new fast X-ray transient
  85. LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a
  86. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
  87. LIGO/Virgo/KAGRA S240422ed: BOOTES-6/DPRT optical upper limits for EP240426a
  88. LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
  89. GRB 240426A: AstroSat CZTI detection
  90. XMM-Newton observation of EP240426a
  91. LIGO/Virgo/KAGRA S240426dl: Identification of a GW compact binary merger candidate
  92. GRB 240414A: NOEMA detection
  93. LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
  94. EP240426a: GMG optical upper limit
  95. LVK S240422ed: Further Swift-XRT followup of three sources
  96. LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate
  97. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  98. LIGO/Virgo/KAGRA S240422ed: PRIME near-infrared observations
  99. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  100. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap

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