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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"

4058 results found.

  1. LIGO/Virgo S190425z: Swift/BAT Counterpart Search
  2. LIGO/Virgo S190425z: SQUEAN Observation
  3. LIGO/Virgo S190425z: MMT Follow-Up Observations
  4. LIGO/Virgo S190425z: INTEGRAL IBIS prompt observation
  5. LIGO-Virgo S190425z: AGILE MCAL observation
  6. LIGO/Virgo S190425z: Lick/KAIT Follow-Up Observations
  7. LIGO/Virgo S190425z: further analysis of INTEGRAL data
  8. LIGO/Virgo S190425z: MAXI/GSC Observations
  9. LIGO/VIRGO S190425z: IceCube Neutrino Search
  10. LIGO/Virgo S190425z: Hobby-Eberly Telescope VIRUS observations of target galaxies.
  11. LIGO/Virgo S190421ar: Fermi-LAT search for a high-energy gamma-ray counterpart
  12. LIGO/VirgoS190425z: HAWC follow-up
  13. LIGO/Virgo S190425z: SAGUARO follow-up observations
  14. LIGO/Virgo S190425z: Potential host galaxies from the GLADE catalog
  15. LIGO/Virgo S190425z: INTEGRAL SPI-ACS prompt observation
  16. LIGO/Virgo S190425z: INTEGRAL prompt observation
  17. LIGO/Virgo S190425z: Identification of a GW compact binary merger candidate
  18. LIGO/Virgo S190425z Global MASTER-Net observations report
  19. LIGO-Virgo S190421ar:Insight-HXMT/HE observation
  20. LIGO/Virgo S190421ar: TAROT-GRANDMA observation report.
  21. LIGO/Virgo S190421ar: Lick/KAIT Follow-Up Observations
  22. LIGO/Virgo S190421ar: Swift/BAT Counterpart Search
  23. LIGO/Virgo S190421ar/G330308: ANTARES neutrino search
  24. LIGO/Virgo S190408an: Liverpool Telescope follow-up imaging observations
  25. LIGO/Virgo S190421ar: MAXI/GSC Observations
  26. LIGO/Virgo S190421ar: INTEGRAL prompt observation
  27. LIGO/Virgo S190421ar: Fermi-GBM Observations
  28. LIGO/Virgo S190421ar Global MASTER-Net observations report
  29. LIGO/Virgo S190421ar: HAWC follow-up
  30. AT LIGO-Virgo S190421ar: AGILE GRID observations
  31. LIGO/VIRGO S190421ar: IceCube Neutrino Search
  32. LIGO/Virgo S190421ar: Identification of a GW compact binary merger candidate
  33. LIGO-Virgo S190421ar: AGILE MCAL observations
  34. LIGO/Virgo S190408an: INTEGRAL follow-up observations
  35. LIGO/Virgo S190412m: SVOM/GWAC observations of the initial skymap
  36. LIGO/Virgo S190408an: Gaia Photometric Alerts transient candidates
  37. LIGO/Virgo S190412m: TAROT-GRANDMA observation report.
  38. LIGO/Virgo S190408an: Gaia Photometric Alerts transient candidate
  39. LIGO/Virgo S190412m: Palomar Gattini-IR Wide-field Infrared Follow-up
  40. LIGO/Virgo S190412m: GOTO optical coverage - no notable counterparts
  41. LIGO/Virgo S190412m: Fermi-LAT search for a high-energy gamma-ray counterpart
  42. LIGO/Virgo S190412m: Swift/BAT data search
  43. LIGO/Virgo S190412m: J-GEM optical/NIR follow-up observations
  44. LIGO/Virgo S190412m: Fermi-GBM Observations
  45. LIGO/Virgo S190412m: MAXI/GSC Observations
  46. LIGO-Virgo S190412m: AGILE GRID observations
  47. LIGO/Virgo S190405ar: Retraction of a GW binary merger candidate
  48. LIGO/Virgo S190412m: Insight-HXMT/HE observation
  49. LIGO/Virgo S190408an: ATLAS observations of the S190412m skymap
  50. LIGO/Virgo S190408an: Gaia Photometric Alerts transient candidate
  51. LIGO/Virgo S190412m/G329483: ANTARES neutrino search
  52. LIGO/Virgo S190412m: Hobby-Eberly Telescope VIRUS observations of target galaxies.
  53. LIGO-Virgo S190412m: Search for neutrino counterparts with IceCube
  54. LIGO/Virgo S190412m: HAWC follow-up
  55. LIGO-Virgo S190412m: AGILE preliminary analysis
  56. LIGO/Virgo S190412m: MASTER early alert observation
  57. LIGO/Virgo S190412m: Identification of a GW binary merger candidate
  58. LIGO/Virgo S190408an: GROND Observations of MASTER OT J154209.55-431742.2
  59. LIGO/Virgo S190408an: Pan-STARRS observations and transients in the skymap
  60. LIGO/Virgo S190408an: MASTER OT J231043.63+470956.4 BOOTES-4 and 10.4m GTC follow-up observations
  61. LIGO/Virgo S190408an: MAXI/GSC Observations
  62. LIGO/Virgo S190408an: GRAWITA optical observations of MASTER OT J231043.63+470956.4
  63. LIGO/Virgo S190408an: CALET Observations
  64. LIGO/Virgo S190408an: TMTS Optical Observation
  65. LIGO/Virgo S190408an: DDOTI/OAN Optical Observations
  66. LIGO/Virgo S190408an: HMT optical observations
  67. LIGO/Virgo S190408an: MASTER 3 OT's more detection
  68. LIGO/Virgo ST190408an: Fermi-LAT search for a high-energy gamma-ray counterpart
  69. LIGO-Virgo S190408an: further AGILE GRID observations after T0
  70. LIGO/Virgo S190408an: SAGUARO follow-up observations
  71. LIGO/Virgo S190408an: MASTER OT is 27 day old ATLAS SN candidate and unrelated
  72. LIGO/Virgo S190408an: Insight-HXMT/HE observation
  73. LIGO/Virgo S190408an: MASTER OT detection
  74. LIGO/Virgo S190408an: Swift/BAT data search
  75. LIGO/Virgo S190408an: KMTNet observation
  76. LIGO-Virgo S190408an: AGILE GRID observations
  77. LIGO/Virgo S190408an: MASTER Global Robotic Net optical observations
  78. LIGO/Virgo S190408an: Identification of a GW binary merger candidate
  79. LIGO-Virgo S190408an: HAWC follow-up
  80. LIGO/Virgo S190408an: Fermi GBM Observation
  81. LIGO-Virgo GW S190408an: J-GEM optical/NIR follow-up observations
  82. LIGO-Virgo S190408an: AGILE MCAL observations
  83. LIGO/Virgo: Announcing the start of Observing Run 3 (O3) and the beginning of the public gravitational-wave alert era
  84. IPN Triangulation of GRB 190329A (long/bright)
  85. GRB 190114C: photometric detection of a SN component
  86. Improved Fermi/GBM GRB localizations
  87. IPN Triangulation of GRB 190304A (long)
  88. IPN Triangulation of GRB 190206A (short/extremely bright)
  89. GRB 190204A: Swift-BAT refined analysis
  90. IPN Triangulation of GRB 190129B (long/extremely bright)
  91. IPN Triangulation of GRB 190118A (long)
  92. CALET Gamma-Ray Burst Monitor: Policy change in the GCN circulars
  93. INTEGRAL observations of the events in the GWTC-1 catalog
  94. Fermi-GBM Observations During Four New GW-Detected BBH Mergers (Correction)
  95. Fermi-GBM Observations During Four New GW-Detected BBH Mergers
  96. IPN Triangulation of GRB 181121A (short)
  97. GRB 180728B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 554505003)
  98. GRB180913A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 558557292)
  99. IPN Triangulation of GRB 181008B (long)
  100. IPN Triangulation of GRB 180824A (short)

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