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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

16292 results found.

  1. GRB 190627A: Montarrenti Observatory optical detection
  2. GRB 190627A: NUTTelA-TAO optical observations
  3. Swift trigger 911102: D50 optical limit
  4. LIGO/Virgo S190426c: Swift UVOT - no new counterpart candidates identified
  5. LIGO/Virgo S190510g: Swift UVOT - no new counterpart candidates identified
  6. GRB 190613A: SEDM Observations
  7. GRB 190613B: Kitab observatory optical upper limit
  8. GRB 190613A: Kitab and AbAO optical upper limit
  9. GRB 190613B: SEDM Observations
  10. GRB 190613A: SEDM Observations
  11. GRB 190610A: Swift/UVOT Upper Limits
  12. GRB 190613B: Optical observation from Asiago Schmidt
  13. GRB 190613B: GROND Detection of the Optical/NIR Afterglow
  14. GRB 190613B: BOOTES-5/JGT early optical observations
  15. GRB 190613B: Optical observations from NOT
  16. GRB 190613B: KAIT Optical Afterglow Confirmation
  17. GRB 190613B: Swift detection of a burst with an optical counterpart
  18. GRB 190613A: MASTER OT detection
  19. GRB 190613A: KAIT Optical Afterglow Confirmation
  20. GRB 190613A: Swift detection of a burst with an optical counterpart
  21. GRB 190611A: Swift/UVOT Upper Limits
  22. GRB 190611A: Optical observations from VLT/FORS2
  23. LIGO/Virgo S190425z: Swift UVOT - no new sources identified, and a summary of the Swift UVOT processing of GW triggers.
  24. GRB 190604B: Kitab observatory optical upper limit
  25. GRB 190530A: optical follow-up observations at Konkoly
  26. GRB 190604B: BOOTES-3 early optical limits
  27. GRB190604B: GROWTH-India telescope followup - no optical counterpart found
  28. S190602aq: MASTER OT detection
  29. GRB 190531B: Swift/UVOT Upper Limits
  30. GRB 190530A: R-band observation from HCT
  31. GRB 190530A: Mondy and AbAO optical observations
  32. GRB 190531B: VLT optical upper limit
  33. GRB 190530A: Konkoly optical observations of the afterglow
  34. GRB 190530A: SAO RAS optical observations
  35. GRB 190531B: MASTER optical observation
  36. GRB 190530A: Swift/UVOT Detection
  37. GRB 190530A: AbAO optical observations
  38. GRB 190530A: Xinglong 2.16m optical observation
  39. GRB 190530A: optical afterglow detection by 5 MASTER telescopes
  40. GRB 190530A: COATLI Optical Detection of the Fading Afterglow
  41. GRB 190530A: Swift-XRT afterglow detection
  42. GRB 190530A: GWAC-F30 optical detection
  43. GRB 190530A: OAJ optical detection
  44. GRB 190530A: NOT photometry and spectroscopy
  45. GRB 190530A: MASTER OT detection
  46. IceCube-190504A: Kanata optical/NIR follow-up observations
  47. LIGO/Virgo S190521r: CNEOST follow-up observations
  48. LIGO/Virgo S190521r: Kanata optical/NIR follow-up observations of the CNEOST Transient
  49. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC-F30 observations.
  50. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC observations.
  51. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC-F30 observations.
  52. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC observations.
  53. LIGO/Virgo S190521r: RATIR Optical and NIR Observations of the CNEOST Transient
  54. LIGO/Virgo S190521r: One optical transient from CNEOST
  55. LIGO/Virgo S190521g: No Counterparts in DDOTI/OAN Optical Observations
  56. LIGO/Virgo S190517h : No counterpart candidate in TAROT-GRANDMA observations.
  57. GRB 190519A: Swift/UVOT Upper Limits
  58. GRB 190511A: Swift/UVOT further analysis
  59. GRB 190515B: Swift/UVOT Upper Limits
  60. GRB 190515B: BOOTES-4/MET and 2.2m CAHA optical limits
  61. GRB 190515B: Optical observations from OSN
  62. GRB 190515B: Kitab Observatory optical upper limit
  63. LIGO/Virgo S190513bm : TAROT-Calern and TAROT-Chile (TCA/TCH)/GRANDMA observation report.
  64. LIGO/Virgo S190510g: DECam-GROWTH optical counterpart candidate DG19qcso
  65. LIGO/Virgo S190510g: AT2019ezb and AT2019far 10.4m GTC spectroscopy
  66. LIGO/Virgo S190510g: Further KMTNet observation of DECam-GROWTH and DESGW candidates
  67. LIGO/Virgo S190510g: Spectroscopic Classification of DECam-GROWTH and DES-GW Candidate DG19fqqk/desgw-190510c with Magellan
  68. LIGO/Virgo S190510g: DOAO Observation
  69. LIGO/Virgo S190510g: KMTNet observation of DECam-GROWTH and DESGW candidates
  70. GRB 190511A: NOT optical afterglow
  71. LIGO/Virgo S190510g: GRAWITA REM and Loiano optical observations
  72. LIGO/Virgo S190510g: GRAWITA VST-ESO PARANAL optical observations
  73. LIGO/Virgo S190510g : Xinglong-60cm upper limit of the GRAWITA REM's OT
  74. LIGO/Virgo S190510g: Unconfirmed OT in PGC 094244
  75. LIGO/Virgo S190510g: Dabancheng/HMT Follow-Up Observations
  76. LIGO/Virgo S190510g: Xinglong/Schmidt Follow-Up Observations
  77. LIGO/Virgo S190510g: Optical Counterpart Candidates from DECam-GROWTH
  78. LIGO/Virgo S190510g: CNEOST Follow-Up Observations
  79. LIGO/Virgo S190510g: J-GEM optical/NIR follow-up observations
  80. LIGO/Virgo S190510g: Updated classification and data quality report
  81. LIGO/Virgo S190510g: Lulin Optical Follow-up Observations
  82. LIGO/Virgo S190510g: GRAWITA REM optical observations
  83. LIGO/Virgo S190510g: HSC Y-band follow-up observation
  84. LIGO/Virgo S190510g: Public DECam Observations
  85. LIGO/Virgo S190426c: Archival VLASS Observations of ZTF19aassfws 14 days prior to Merger
  86. GRB 190508A: GOTO optical search - no counterparts
  87. LIGO/Virgo S190503bf: TAROT-GRANDMA observation report
  88. GRB 190507B: GOTO optical counterpart search
  89. GRB 190501A: Swift XRT and UVOT Observations
  90. IceCube-190504A: MASTER optical monitoring analysis
  91. LIGO/Virgo S190426c: Update on Source Classification
  92. IceCube-190504A: MASTER optical follow-up observations
  93. IceCube-190503A: Lick/KAIT Follow-Up Observations
  94. GRB 190501A: GOTO optical counterpart search
  95. LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
  96. LIGO/Virgo S190426c: Gaia19boq 0.6m BOOTES-5/JGT, 1.5m OSN and 10.4m GTC observations
  97. LIGO/Virgo S190426c: ZTF19aaslzjf, ZTF19aasmftm and ZTF19aasmddt 1.5m OSN and 10.4m GTC observations
  98. LIGO/Virgo S190426c: ZTF pre-detections of Gaia19bpm AT2019ehs
  99. LIGO/Virgo S190425z: ZTF pre-detections of Gaia19bpt AT2019ehz
  100. LIGO/Virgo S190426c: Swift rapid follow-up observations of S190425z and S190426c and URL for observation log for all future events

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