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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"
  1. LIGO/Virgo S190828l: No counterpart candidates in HAWC observations
  2. LIGO/Virgo S190828j: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  3. LIGO/Virgo S190828j: No counterpart candidates in HAWC observations
  4. LIGO/Virgo S190828j: No counterpart candidates in AGILE-MCAL observations
  5. LIGO/Virgo S190828j: Identification of a GW compact binary merger candidate
  6. LIGO/Virgo S190814bv: Correction of ASKAP coordinates
  7. LIGO/Virgo S190814bv: DESGW non-detection of AT2019osy/ASKAP 005547-270433
  8. LIGO/Virgo S190814bv: Palomar 200-in spectroscopic redshift and host galaxy properties of ASKAP source AT2019osy
  9. Fermi trigger No 588597173 Global MASTER-Net observations report
  10. LIGO/Virgo S190814bv: Optical non-detection of radio source AT2019osy from CFHT
  11. Fermi GBM-190816: Eight additional candidates from the Zwicky Transient Facility
  12. GRB 190827A: BALROG localization (Fermi Trigger 588597173 / GRB 190827467)
  13. GRB 190827A: Fermi GBM Final Real-time Localization
  14. LIGO/Virgo S190814bv: DECam-GROWTH detection of an optical counterpart to the radio source AT2019osy
  15. LIGO/Virgo S190814bv: Detection of a candidate radio counterpart with ASKAP
  16. LIGO/Virgo S190814bv: Final list of candidates from the DESGW coadd analysis from the week long search campaign
  17. LIGO/Virgo S190814bv: CFHTphotometryof AT2019npv
  18. LIGO/Virgo S190814bv: SOAR spectroscopy of DECam candidates AT2019npw and AT2019num
  19. LIGO/Virgo S190814bv : Magellan IMACS Spectrum of AT2019npv classified as a Type Ib supernova
  20. GRB 190824A, Swift-BAT refined analysis
  21. LIGO/Virgo S190814bv: SALT optical spectrum of candidate DG19aqbkc
  22. LIGO/Virgo S190814bv: Radio non-detection of DG19wxnjc/AT2019npv with the VLA
  23. GRB 190824A: Swift/UVOT Upper Limits
  24. LIGO/Virgo S190814bv: Keck II NIRES classification of DG19wxnjc/AT2019npv as a stripped envelope supernova
  25. LIGO/Virgo S190814bv: LCO Photometry of DG19wxnjc/AT2019npv
  26. GRB 190823A: Swift-XRT observations
  27. Fermi trigger No 588398821 Global MASTER-Net observations report
  28. LIGO/Virgo S190814bv: MASTER prediscovery and postdiscovery observations DECam candidate DG19wxnjc/AT2019npv field
  29. GRB 190816A: Swift-XRT afterglow detection
  30. LIGO/Virgo S190814bv: No radio counterpart to DG19wxnjc/AT2019npv in ASKAP observations
  31. GRB 190825A: Fermi GBM Final Real-time Localization
  32. GRB 190824A: Swift-XRT refined Analysis
  33. GRB 190824A: Fermi GBM observation
  34. LIGO/Virgo S190814bv: Archival detection of DG19wxnjc/AT2019npv in DES data
  35. Fermi trigger No 588350802 Global MASTER-Net observations report
  36. GRB 190824A: Enhanced Swift-XRT position
  37. Fermi GBM-190816: Updated localization of subthreshold GRB-GW candidate
  38. GRB 190821A: Swift-BAT refined analysis
  39. GRB 190824A: Swift detection of a burst
  40. GRB 190824A: Fermi GBM Final Real-time Localization
  41. LIGO/Virgo S190814bv: Keck NIRES spectroscopy of DG19wxnjc/AT2019npv
  42. LIGO/Virgo S190814bv: Photometric Evolution of DECAM candidates
  43. GRB 190823A: Tiled Swift observations
  44. LIGO/Virgo S190814bv: DESGW photometry of AT2019npv
  45. LIGO/Virgo S190814bv: GROND follow-up observations of AT2019npv
  46. GRB 190823A: MAXI/GSC detection
  47. LIGO/Virgo S190814bv: Further Pan-STARRS z-band observations and AT2019npv photometry
  48. LIGO/Virgo S190814bv: WHT spectroscopy of the host of AT2019npv
  49. Fermi trigger No 588185734 Global MASTER-Net observations report
  50. Fermi GBM-190816: Coverage and upper limits from MAXI/GSC observations
  51. Fermi trigger No 588115134 Global MASTER-Net observations report
  52. GRB 190821A: Swift/UVOT Upper Limits
  53. LIGO/Virgo S190814bv: NIR imaging follow-up of ASKAP transient
  54. GRB 190821A: MASTER VWFC syncronous optical observations
  55. LIGO/Virgo S190814bv: ENGRAVE VLT/HAWK-I observations and archival detection of the CFHT candidate
  56. Fermi GBM-190816: MASTER-Net optical observation report
  57. LIGO/Virgo S190814bv: No radio counterpart detected in ASKAP observations
  58. GRB 190821A: Swift-XRT refined Analysis
  59. LIGO/Virgo S190814bv: a potential faint optical counterpart in CFHT imaging
  60. LIGO/Virgo S190822c: Retraction of GW compact binary merger candidate
  61. LIGO/Virgo S190822c: CLU/NED Galaxies in the 50% Localization Volume
  62. LIGO/Virgo S190822c Global MASTER-Net observations report
  63. LIGO/Virgo S190822c: Upper limits from IceCube neutrino searches
  64. LIGO/Virgo S190814bv: new candidate from DESGW
  65. LIGO/Virgo S190814bv: No Optical Counterpart Candidates in Second-Epoch Lick/KAIT Observations
  66. GRB 190821A: Enhanced Swift-XRT position
  67. GRB 190821A: Fermi GBM observation
  68. Fermi GBM-190816: Upper Limits from Swift/BAT Observations
  69. GRB 190821A: MASTER do not see any afterglow candidate
  70. Fermi GBM-190816: Correction from the Zwicky Transient Facility
  71. GRB 190821A: T60 Les Makes optical detection of the afterglow
  72. Fermi GBM-190816: Four additional candidates from the Zwicky Transient Facility
  73. Swift GRB190821.72 Global MASTER-Net observations report
  74. Fermi trigger No 588100239 Global MASTER-Net observations report
  75. GRB 190821A: Swift detection of a burst
  76. Fermi GBM-190816: No counterpart candidates in Fermi-LAT observations
  77. LIGO/Virgo S190814bv: further candidates from DESGW
  78. Fermi GBM-190816: AGILE in SAA at T0
  79. LIGO/Virgo S190814bv: SOAR spectroscopy of AT2019noq and AT2019ntn
  80. LIGO/Virgo S190814bv: No Counterpart Candidates in Las Cumbres Observatory Galaxy Targeted Search
  81. Fermi GBM-190816: ZTF19abqanpy 10.4m GTC spectroscopy
  82. Fermi-LAT Gamma-ray Observations of IceCube-190819A
  83. LIGO/Virgo S190814bv: AT2019nqq 10.4m GTC spectroscopy
  84. Fermi GBM-190816: One candidate counterpart from the Zwicky Transient Facility
  85. LIGO/Virgo S190814bv: Further Pan-STARRS observations and transient sources
  86. LIGO/Virgo S190814bv: RATIR Optical observations of DECam transients
  87. LIGO/Virgo GBM-190816: no counterpart candidates in the Swift/BAT Observations
  88. Fermi GBM-190816: Upper limits from IceCube neutrino searches
  89. IceCube-190819A: Upper limits from a search for additional neutrino events in IceCube
  90. IceCube-190819A: MASTER analysis
  91. IceCube-190819A - HAWC follow-up
  92. Fermi GBM-190816: No counterpart candidates in HAWC observations
  93. LIGO/Virgo S190814bv: No neutrino candidates at Pierre Auger Observatory
  94. Fermi GBM-190816+LIGO/Virgo : no neutrino counterpart candidate in ANTARES search
  95. Fermi GBM-190816: Location-dependent upper limits from INTEGRAL/SPI-ACS prompt observation
  96. Fermi GBM-190816: A subthreshold GRB candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  97. GRB 190816A: Swift-BAT refined analysis
  98. IceCube-190819A: Upper limits from Fermi-GBM Observations
  99. IceCube-190819A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  100. IceCube-190819A - IceCube observation of a high-energy neutrino candidate event

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