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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"

19548 results found.

  1. GRB 170419A: Swift detection of a burst
  2. Swift Trigger 748858: Zadko observatory - Gingin optical observations
  3. Swift Trigger 748858: a possible GRB
  4. LIGO/Virgo G275404: DLT40 follow-up observation
  5. GRB 170409A: TAROT Reunion observatory optical observations
  6. GRB 170405A: SMARTS optical/IR afterglow observations
  7. GRB 170317A: SAO RAS optical observations
  8. GRB170405A, Swift-UVOT Detection
  9. GRB 170405A, Swift-BAT refined analysis
  10. GRB 170405A: Etelman observatory optical observations
  11. GRB 170405A: Swift-XRT refined Analysis
  12. GRB 170405A: RATIR Optical and NIR Observations
  13. Trigger 745966: Swift detection of 4U1850-03
  14. GRB 170405A: ISON/Terskol optical observations
  15. GRB 170405A: Watcher optical detection
  16. GRB 170405A: Redshift from OSIRIS/GTC
  17. GRB 170405A: TAROT Reunion observatory optical observations
  18. GRB 170405A: Enhanced Swift-XRT position
  19. GRB 170405A: Swift detection of a burst with an optical counterpart
  20. LIGO/Virgo G275404: European VLBI Network (EVN) follow-up of the near-IR transient in the AGL J1914+1043 field
  21. IPN Triangulation of GRB 170403A (short)
  22. Swift Trigger 745090 is a noise trigger near NGC 5195
  23. Fermi-LAT Gamma-ray Observations of IceCube-170321
  24. Swift triggered on SAX J1806.5-221
  25. GRB 170330A: Swift-BAT refined analysis
  26. DOAO 1m telescope V, R, I observation of GRB 170317A
  27. GRB 170331A: Swift/UVOT Upper Limits
  28. IceCube-170321A: Swift-XRT observations
  29. GRB 170330A: Enhanced Swift-XRT position
  30. GRB 170331A: Enhanced Swift-XRT position
  31. GRB 170330A: Swift/UVOT Detection of a Fading Afterglow
  32. LIGO/Virgo G275697: LOFAR follow-up
  33. GRB 170331A: Swift detection of a burst
  34. GRB 170330A: Swift detection of a burst
  35. GRB 170325A, Swift-BAT detection of a short GRB
  36. LIGO/Virgo G277583: INTEGRAL search for an X-ray and gamma-ray counterpart
  37. LIGO/Virgo G275697: AMI Large Array Search for a Radio Afterglow
  38. INTEGRAL SPI-ACS observation of AMON IceCube EHE 80305071 129307
  39. IPN Triangulation of GRB 170320A (long/intense)
  40. GRB 170317A: Mondy optical observations
  41. GRB 170318B: RATIR Optical and NIR Observations
  42. GRB 170317A: RATIR Optical and NIR Observations
  43. GRB 170318B: Swift/UVOT Upper Limits
  44. GRB 170318B: Swift-XRT refined Analysis
  45. GRB 170318A: Swift-XRT refined Analysis
  46. LIGO/Virgo G277583: CALET Observations
  47. GRB 170318A: RATIR Optical and NIR Observations
  48. GRB 170318A: Swift/UVOT Upper Limits
  49. GRB 170317A: RATIR Optical and NIR Observations
  50. GRB 170318B: Enhanced Swift-XRT position
  51. GRB 170318B: Swift detection of a burst
  52. GRB 170318A: Enhanced Swift-XRT position
  53. GRB 170318A: Swift detection of a burst
  54. GRB 170317A: MITSuME Okayama Optical Observation
  55. LIGO/Virgo G277583: AstroSat CZTI upper limits
  56. GRB 170317A: Swift/UVOT Detection
  57. GRB 170317A: Mondy optical observations
  58. GRB 170317A: MITSuME Okayama Ks-band upper-limit
  59. GRB 170317A: Swift-XRT refined Analysis
  60. IceCube-170312A: Swift-XRT observations
  61. GRB 170317A: GMG observation
  62. GRB 170317A: Enhanced Swift-XRT position
  63. GRB 170317A: ISON-Ussuriysk aferglow confirmation
  64. GRB 170317A: Swift detection of a burst with an optical counterpart
  65. LIGO/Virgo G277583: Swift/BAT data search
  66. LIGO/Virgo G277583: ATLAS17cck is likely a minor planet
  67. LIGO/Virgo G277583: GROND follow up of ATLAS17cck
  68. LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
  69. LIGO/Virgo G277583: ERRATUM LV GCN 20871: TAROT Calern (TCA) observations
  70. LIGO/Virgo G277583: TAROT Calern (TCA) observations
  71. LIGO/Virgo G277583: SVOM/Mini-GWAC observations of the initial skymap
  72. LIGO/Virgo G275404: Medicina radio follow-up of near-infrared
  73. Fermi GBM trigger 510642159/170308210 is not a GRB
  74. LIGO/Virgo G277583 ANTARES search
  75. Konus-Wind observation of GRB 170311B
  76. LIGO/Virgo G270580: optical observations and classification of PS and MASTER sources
  77. IPN Triangulation of GRB 170311B (long/very intense)
  78. GRB 170311A: VLT observations
  79. INTEGRAL observation of IceCube HESE 65274589 129281
  80. GRB 170311A: Swift/UVOT Upper Limits
  81. GRB 170311A: Enhanced Swift-XRT position
  82. GRB 170311A: GROND upper limits
  83. GRB 170311A: Swift detection of a burst
  84. GRB 170306A: GROND afterglow detection
  85. LIGO/Virgo G275404: Swift-XRT observations of sources in the AGILE error region
  86. LIGO/Virgo G275697: Swift-XRT source 23 is fading
  87. LIGO/Virgo G275404 and AGL J1914+1043: INTEGRAL follow-up
  88. GRB 170306B: Swift-XRT observations
  89. GRB 170306A: Swift-XRT refined Analysis
  90. GRB 170306B: Tiled Swift observations
  91. IPN Triangulation of GRB 170305A (short)
  92. GRB 170306A: Swift/UVOT Upper Limits
  93. GRB 170306A: GROND observations
  94. LIGO/Virgo G275697: Further Swift-XRT sources
  95. GRB 170306A: LCO Cerro Tololo observations
  96. GRB 170306A: Swift detection of a burst
  97. LIGO/Virgo G275697: Further Swift-XRT sources
  98. LIGO/Virgo G275404: HAWC follow-up
  99. LIGO/Virgo G275697: Further Swift-XRT sources
  100. LIGO/Virgo G275697: Further Swift-XRT sources

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