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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"

3674 results found.

  1. LIGO/Virgo S190718y: No counterpart candidates in CNEOST
  2. LIGO/Virgo S190718y: No counterpart candidates in KAIT observations
  3. LIGO/Virgo S190718y: Upper limits from CALET observations
  4. Fermi trigger No 584977168 Global MASTER-Net observations report
  5. Fermi trigger No 584929684 Global MASTER-Net observations report
  6. IPN triangulation of GRB 190706C (long/very bright)
  7. LIGO/Virgo S190707q: Upper limits from CALET observations
  8. LIGO/Virgo S190706ai: No counterpart candidates in KAIT observations
  9. Fermi trigger No 584007338 Global MASTER-Net observations report
  10. Trigger 913042: Swift triggered on noise peak
  11. LIGO/Virgo S190630ag: no counterpart candidate in the SVOM/GWAC observations
  12. LIGO/Virgo S190701ah: KMTNet Observation
  13. LIGO/Virgo S190701ah: No transient candidates from CALET observations
  14. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  15. GRB 190627A: GMG observation at the second epoch
  16. GRB 190627A: NUTTelA-TAO optical counterpart observations
  17. GRB 190628A: Fermi GBM Final Real-time Localization
  18. Fermi trigger No 583111521 Global MASTER-Net observations report
  19. Swift Trigger 911102: a possible GRB
  20. Fermi trigger No 582856902 Global MASTER-Net observations report
  21. Fermi trigger No 582759998 Global MASTER-Net observations report
  22. Fermi trigger No 582615488 Global MASTER-Net observations report
  23. Fermi trigger No 582304592 Global MASTER-Net observations report
  24. GRB 190613B: SEDM Observations
  25. Fermi trigger No 582115625 Global MASTER-Net observations report
  26. IPN Triangulation of GRB 190611B
  27. Fermi trigger No 581889628 Global MASTER-Net observations report
  28. Fermi trigger No 581882394 Global MASTER-Net observations report
  29. LIGO/Virgo S190602aq: Upper limits from CALET observations
  30. LIGO/Virgo S190602aq: Coverage and upper limits from MAXI/GSC observations
  31. Fermi Fermi trigger No 581002688 Global MASTER-Net observations report
  32. GRB 190530A: Swift/UVOT Detection
  33. GRB 190530A: Swift-XRT afterglow detection
  34. GRB 190530A: GWAC-F30 optical detection
  35. GRB 190530A: OAJ optical detection
  36. GRB 190530A: AGILE/GRID analysis
  37. LIGO/Virgo S190519bj: AstroSat CZTI upper limits
  38. LIGO/Virgo S190521r: CNEOST follow-up observations
  39. Fermi GRB190525.67 Global MASTER-Net observations report
  40. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC observations.
  41. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC-F30 observations.
  42. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC observations.
  43. LIGO/Virgo S190521g: No Counterparts in DDOTI/OAN Optical Observations
  44. S190519bj: No transient candidates from CALET observations
  45. LIGO/Virgo S190512at: SVOM/GWAC-F60A observations
  46. LIGO/Virgo S190519bj Global MASTER-Net observations report
  47. LIGO/Virgo S190517h: CALET Observations
  48. LIGO/Virgo S190518bb Global MASTER-Net observations report
  49. LIGO/Virgo S190517h Global MASTER-Net observations report
  50. LIGO/Virgo S190513bm: Swope follow-up observations
  51. LIGO/Virgo S190513bm : TAROT-Calern and TAROT-Chile (TCA/TCH)/GRANDMA observation report.
  52. LIGO/Virgo S190513bm: CALET Observations
  53. LIGO/Virgo S190513bm: Lick/KAIT Follow-Up Observations
  54. LIGO/Virgo S190510g: Swift-XRT observations and results
  55. LIGO/Virgo S190512at: CALET Observations
  56. LIGO/Virgo S190513bm: AGILE GRID observations
  57. LIGO/Virgo S190513bm: INTEGRAL prompt observation
  58. LIGO/Virgo S190513bm: AGILE MCAL observation
  59. LIGO/Virgo S190513bm Global MASTER-Net observations report
  60. LIGO/Virgo S190510g: Pan-STARRS and ATLAS observations and candidates
  61. LIGO/Virgo S190512at Global MASTER-Net observations report
  62. GRB 190512A: Fermi GBM observation
  63. LIGO/Virgo S190510g: CALET Observations
  64. LIGO/Virgo S190510g: MASTER OT detection inside low surface brightness galaxy
  65. GRB 190511A: Fermi GBM observation
  66. LIGO/Virgo S190510g: DESGW counterpart candidates over 80% of the GW localization area
  67. LIGO/Virgo S190510g: Dabancheng/HMT Follow-Up Observations
  68. LIGO/Virgo S190510g: SOAR/Goodman follow-up observations
  69. LIGO/Virgo S190510g: CNEOST Follow-Up Observations
  70. LIGO/Virgo S190510g: J-GEM optical/NIR follow-up observations
  71. LIGO/Virgo S190510g: Lick/KAIT Follow-Up Observations
  72. LIGO/Virgo S190510g: Lulin Optical Follow-up Observations
  73. LIGO/Virgo S190425z: CAHA-GRANDMA Observation of the Swift UVOT Source
  74. LIGO/Virgo S190426c: Archival VLASS Observations of ZTF19aassfws 14 days prior to Merger
  75. Fermi GRB190507.97 Global MASTER-Net observations report
  76. Fermi GRB190507.27 Global MASTER-Net observations report
  77. IceCube-190504A: MASTER optical monitoring analysis
  78. Fermi Trigger 578903308 / GRB 190507270 / GRB190507A: BALROG localization
  79. GRB 190507A: Fermi GBM Final Real-time Localization
  80. Fermi GRB190505.05 Global MASTER-Net observations report
  81. Fermi GRB190504.68 Global MASTER-Net observations report
  82. LIGO/Virgo S190503bf Global MASTER-Net observations report
  83. IceCube-190503A: Lick/KAIT Follow-Up Observations
  84. IPN triangulation of GRB 190504A (short)
  85. LIGO/Virgo S190503bf: Fermi-GBM Observations
  86. LIGO/Virgo S190503bf: INTEGRAL prompt observation
  87. LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
  88. Fermi GRB190501.79 Global MASTER-Net observations report
  89. LIGO/Virgo S190426c: PS1 historical detections and ZTF photometry of Gaia19boq AT2019egk
  90. LIGO/Virgo S190425z: 1.3-m optical imaging of UVOT transient field
  91. LIGO/Virgo S190426c: YAHPT Optical Observation
  92. LIGO/Virgo S190425z: KPED Follow-Up of ZTF transients
  93. LIGO/Virgo S190426c: GRAWITA transients from Asiago Schmidt wide field observations
  94. LIGO/Virgo S190425z: DECam Observations of the UVOT Candidate Region
  95. LIGO/Virgo S190426c: Continued LOAO Observation
  96. LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
  97. Fermi Trigger 578170097 / GRB 190428783 / GRB190428A: BALROG localization
  98. LIGO/Virgo S190426c: Additional Candidates from the Zwicky Transient Facility
  99. LIGO/Virgo S190426c: Continued infrared wide-field search with Palomar Gattini-IR
  100. LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometric follow-up observation of the Swift/UVOT Transient

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