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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"

28045 results found.

  1. GRB 190821A: T60 Les Makes optical detection of the afterglow
  2. GRB 190821A: Swift detection of a burst
  3. Fermi GBM-190816: No counterpart candidates in Fermi-LAT observations
  4. Fermi-LAT Gamma-ray Observations of IceCube-190819A
  5. LIGO/Virgo S190814bv: RATIR Optical observations of DECam transients
  6. LIGO/Virgo GBM-190816: no counterpart candidates in the Swift/BAT Observations
  7. Fermi GBM-190816: Upper limits from IceCube neutrino searches
  8. IceCube-190819A: Upper limits from a search for additional neutrino events in IceCube
  9. IceCube-190819A - HAWC follow-up
  10. Fermi GBM-190816: No counterpart candidates in HAWC observations
  11. LIGO/Virgo S190814bv: No neutrino candidates at Pierre Auger Observatory
  12. Fermi GBM-190816+LIGO/Virgo : no neutrino counterpart candidate in ANTARES search
  13. Fermi GBM-190816: Location-dependent upper limits from INTEGRAL/SPI-ACS prompt observation
  14. Fermi GBM-190816: A subthreshold GRB candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  15. GRB 190816A: Swift-BAT refined analysis
  16. IceCube-190819A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  17. LIGO/Virgo S190814bv: No strong counterpart candidates in Swift/XRT observations
  18. GRB 190816A: Swift-XRT observations
  19. LIGO/Virgo S190814bv: No candidates from image subtraction in DCT galaxy targeted search
  20. LIGO/Virgo S190814bv: WIRC NIR imaging follow-up of DECam transients
  21. LIGO/VIRGO S190814bv: AbAO non-detection of AT2019nme
  22. LIGO/Virgo S190814bv: No candidates found in J-GEM follow-up observations
  23. LIGO/Virgo S190814bv: Fermi-LAT search for a high-energy gamma-ray counterpart
  24. LIGO/Virgo S190814bv : No Counterpart Candidates in Continued Galaxy Targeted Search with Magellan
  25. LIGO/Virgo S190814bv: No candidates found in J-GEM follow-up observations
  26. LIGO/VIRGO S190814bv: No candidates from ATLAS observations
  27. LIGO/Virgo S190814bv: No candidates from DCT galaxy targeted search and observations of DECam-GROWTH candidates
  28. LIGO/Virgo S190814bv: GROND imaging of candidate galaxies
  29. SUBJECT: LIGO/Virgo S190814bv: GRAWITA VST-ESO PARANAL observations
  30. S190814bv: MASTER analysis of DECam-GROWTH candidates
  31. LIGO/Virgo S190814bv: Konus-Wind observations
  32. LIGO/Virgo S190814bv : No Counterpart Candidates in Galaxy Targeted Search with Magellan
  33. LIGO/Virgo S190814bv: Upper limits from Insight-HXMT/HE observations
  34. GRB 190813A: Insight-HXMT/HE detection
  35. GRB 190814A: Insight-HXMT/HE detection
  36. LIGO/Virgo S190814bv: No Candidates Found in Wide-Field Infrared Search with Palomar Gattini-IR
  37. Fermi trigger No 587505927 Global MASTER-Net observations report
  38. LIGO/VIRGO S190814bv: No candidates from Pan-STARRS and non-detection of AT2019nme
  39. LIGO/Virgo S190814bv: No Counterparts in DDOTI/OAN Optical Observations
  40. LIGO/Virgo S190814bv: no counterpart candidates in Thacher imaging
  41. LIGO/Virgo S190814bv: no counterpart candidates in Swope imaging
  42. LIGO/Virgo S190814bv: no counterpart candidates in Nickel/Direct imaging and non-detections of 2019nmd and 2019nme
  43. LIGO/Virgo S190814bv: ATLAS forced photometry non-detections of DESGW candidates
  44. Non-detection of DESGW-190814a in ZTF forced photometry
  45. LIGO/Virgo S190814bv: no counterpart candidates in Keck I MOSFIRE imaging
  46. LIGO/Virgo S190814bv: KMTNet observation
  47. LIGO/Virgo S190814bv: No counterpart candidates in the Swift/BAT Observations
  48. LIGO/Virgo S190814bv: MeerLICHT coverage second preliminary skymap
  49. LIGO/Virgo S190814bv: no candidates from GOTO imaging observations
  50. LIGO/Virgo S190814bv: Upper limits from AGILE-GRID observations
  51. LIGO/Virgo S190814bv: Update on Sky-Localization and Source-Classification
  52. LIGO/Virgo S190814bv : no neutrino counterpart candidate in ANTARES search
  53. LIGO/Virgo S190814bv: Coverage and upper limits from MAXI/GSC observations
  54. LIGO/Virgo S190814bv: No counterpart candidates in AGILE-MCAL observations
  55. LIGO/Virgo S190814bv: Upper limits from Fermi-GBM Observations
  56. LIGO/Virgo S190814bv: Identification of a GW compact binary merger candidate
  57. LIGO/Virgo S190814bv: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  58. LIGO/Virgo S190814bv: Upper limits from IceCube neutrino searches
  59. HAWC-190806A: Upper limits from Insight-HXMT/HE observations
  60. FRB 190806: MASTER optical observation
  61. IPN triangulation of GRB 190810A (short)
  62. Fermi trigger No 587084236 Global MASTER-Net observations report
  63. HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
  64. HAWC-190806A: Swift-XRT observations
  65. HAWC Burst Alert 1008846_957: Konus-Wind observations
  66. GRB 190726A: Insight-HXMT/HE detection
  67. LIGO/Virgo S190728q: New optical candidates from the DESGW program
  68. LIGO/Virgo S190808ae: Coverage and upper limits from MAXI/GSC observations
  69. LIGO/Virgo S190808ae: No counterpart candidates in HAWC observations
  70. LIGO/Virgo S190808ae: One Coincident Neutrino Candidate from IceCube Search
  71. LIGO/Virgo S190808ae: Identification of a GW compact binary merger candidate
  72. GRB 190808B: BALROG localization (Fermi Trigger 586980202 / GRB 190808752)
  73. HAWC Burst Alert 1008846_957: IceCube Neutrino Search
  74. GRB 190804B: Swift-XRT afterglow detection
  75. Alert from the HAWC Burst Monitor
  76. GRB 190805B: Swift-XRT observations
  77. GRB 190805B: Fermi GBM detection
  78. GRB 190804B: Swift-XRT observations
  79. GRB 190805B: BALROG localization (Fermi Trigger 586673165 / GRB 190805199)
  80. GRB 190805B: MAXI/GSC detection
  81. MAXI GRB190804.33 Global MASTER-Net observations report
  82. GRB 190804C: BALROG localization (Fermi Trigger 586638042 / GRB 190804792)
  83. GRB 190804B: MAXI/GSC detection
  84. GRB 190731A: Swift/UVOT Upper Limits
  85. GRB 190731A: no OT detected by MASTER
  86. IceCube 190730A: No counterpart candidates or blazar activity in GOTO observations
  87. GRB 190731A: Swift-XRT afterglow detection
  88. IPN Triangulation of GRB 190731A
  89. LIGO/Virgo S190727h: Updated sky localization
  90. Fermi trigger No 586305505 Global MASTER-Net observations report
  91. Fermi trigger No 586305505 Global MASTER-Net observations report
  92. IceCube-190730A: Upper limits from a search for additional neutrino events in IceCube
  93. Fermi-LAT Gamma-ray Observations of IceCube-190730A
  94. IceCube-190730A - HAWC follow-up
  95. IceCube 190730A: one weakly associated counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  96. LIGO/Virgo S190728q: Optical transients from Pan-STARRS coverage during first 2 nights
  97. LIGO/Virgo S190728q: GRAWITA VST-ESO PARANAL observations
  98. LIGO/Virgo S190728q/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  99. S190728q: MASTER multiple previous outbursts detection of ZTF19abjethn=AT2019lvs
  100. GRB 190727B: Swift-BAT refined analysis

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