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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').
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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"

5826 results found.

  1. GRB 171007A: Swift-XRT refined Analysis
  2. GRB 171004A: Correction to RATIR Astrometry and Photometry
  3. GRB 171004A: RATIR Optical and NIR Observations
  4. GRB 171004A: Swift detection of a burst
  5. LIGO/Virgo G299232: LOFAR follow-up
  6. GRB 171003A: Swift detection of a burst or a Galactic Transient
  7. LIGO/Virgo G298048: Record of all e-MERLIN results to date on SSS17a
  8. LIGO/Virgo G299232/GW170825: serendipitous XMM-Newton slew observations
  9. LIGO/Virgo G298936/GW170823: serendipitous XMM-Newton slew observations
  10. GRB 170728B: Kottamia R-band observation
  11. IceCube-170922A: Swift-XRT observations
  12. LIGO/Virgo G298048: MWA Observations of Error Region
  13. IceCube-170922A: HAWC follow-up
  14. GRB 170906A: Insight-HXMT detection
  15. GRB 170921C: Insight-HXMT detection
  16. INTEGRAL SPI-ACS observation of AMON IceCube-170922A
  17. GRB 170921A: RATIR Optical Afterglow Detection and NIR Observations
  18. LIGO/Virgo G298048: SRT observations of SSS17a in NGC 4993
  19. GRB 170918A: Insight-HXMT detection
  20. GRB 170921A: Nanshan optical upper limit
  21. GRB 170921A: MITSuME Okayama upper limits
  22. LIGO/Virgo G298048: SSS17a photometry of CHILESCOPE observatory
  23. LIGO/Virgo G298048: Milliarcsecond imaging of the NGC 4993 central radio source
  24. Fermi-GBM GRB misclassifications
  25. GRB 170912C: Insight-HXMT detection
  26. LIGO/VIRGO G298048: MeerKAT observations of SSS17a
  27. LIGO/Virgo G297595: NIR Observations following GW170814
  28. LIGO/Virgo G298048: Danish Telescope Observations of SSS17a/DLT17ck
  29. LIGO/Virgo G298048: AST3-2 observations of SSS17a/DLT17ck from Antarctica
  30. GRB 170912A: Prompt enhanced Swift-XRT position
  31. Konus-Wind observation of GRB 170904A
  32. LIGO/Virgo G298048: ATCA observations of of SSS17a in NGC 4993
  33. GRB 170906C: COATLI Observations
  34. GRB 170906A: MASTER-OAFA (Argentina) early automatic OT detection
  35. IPN Triangulation of GRB 170904A (long/very bright)
  36. GRB 170901B: Insight-HXMT detection
  37. GRB 170904A: Insight-HXMT detection
  38. LIGO/VIRGO G298048: Precise position of SSS17a based on HST and Gaia
  39. LIGO/Virgo G299232: LOFAR follow-up
  40. GRB 170903A: UAFO /ISON optical upper limit
  41. GRB 170903A: MITSuME Okayama upper limits
  42. GRB 170903A: Nanshan optical upper limit
  43. Swift Triggers on MAXI J1535-571
  44. LIGO/Virgo G297595: DECam observations of BBH merger region of interest
  45. LIGO/Virgo G298048: Chandra monitoring of the X-ray emission from SSS17a
  46. LIGO/Virgo G298048: Continued X-ray monitoring and X-ray detection of GW170817 [erratum]]
  47. LIGO/Virgo G299232: GRAWITA Asiago optical observations
  48. LIGO/Virgo G298936: PIRATE observations
  49. LIGO/Virgo G298048: GMRT Follow-up of SSS17a at 1.4 GHz
  50. LIGO/Virgo G299232: GRAWITA Campo Imperatore optical observations
  51. LIGO/Virgo G299232: PIRATE observations of MASTER OT J033744.97+723159.0
  52. LIGO/Virgo G298048: ALMA upper limits on 98 GHz emission from SSS17a
  53. LIGO/Virgo G298048: Further ATCA follow-up of SSS17a in NGC 4993
  54. LIGO/Virgo G299232 TZAC/TAROT observations
  55. LIGO/Virgo G299232/PGWB170825.55: MASTER Global-Net OT inside NGC1343 discovery
  56. GRB 170827A: Swift detection of a burst
  57. LIGO/VIRGO G298048: INAF VST-ESO PARANAL observations of NGC4993
  58. GRB 170822A: AstroSat CZTI detection
  59. LIGO/Virgo G298048: MASTER Global-Net early optical observations and the Possible KiloNova SSS17a in NGC 4993 photometry and merging rate
  60. LIGO/Virgo G298048: HAWC follow-up
  61. LIGO/Virgo G298048: LWA radio observations
  62. Konus-Wind observation of GRB 170822A
  63. LIGO/Virgo G298048: INTEGRAL pointed follow-up observations
  64. LIGO/Virgo G298048: ATCA follow-up of SSS17a in NGC 4993
  65. LIGO/Virgo G298048: Chandra X-ray observations
  66. LIGO/Virgo G298048: observations of optical counterpart candidate with CHILESCOPE observatory
  67. GRB 170822A:BOOTES-5/JGT optical afterglow candidate
  68. GRB 170822A: Swift detection of a burst
  69. LIGO/Virgo G298048: MWA Observations of Error Region
  70. LIGO/Virgo G298048: VLA observation at 15 GHz
  71. LIGO/Virgo G298048: observations of optical counterpart candidate with CHILESCOPE observatory
  72. LIGO/Virgo G298048: ATCA 8.5 GHz observations of galaxies in the localisation volume
  73. LIGO/Virgo G298048: NuSTAR limits on X-ray emission
  74. LIGO/Virgo G298048: ASKAP follow up
  75. LIGO/Virgo G298048: TOROS optical counterpart search
  76. LIGO/Virgo G298048: VLA observation at 6 GHz
  77. LIGO/Virgo G298048: GROND observations of candidate optical counterpart
  78. LIGO/Virgo G298048: VLT linear polarimetry
  79. LIGO/Virgo G298048: Further VLA Observations
  80. LIGO/Virgo G298048: HSC observations of the OT candidate of G298048
  81. LIGO/Virgo G298048: GROND photometry of candidate optical counterpart reveals brightening in the NIR
  82. LIGO/Virgo G298048: Rapid Evolution of Possible Counterpart
  83. LIGO/Virgo G298048: ATCA upper limits on radio emission from optical source SSS17a in NGC 4993
  84. LIGO/Virgo G298048: Brightening of Possible Counterpart
  85. LIGO/Virgo G298048: AGILE-GRID analysis of the potential counterpart field
  86. LIGO/Virgo G298048: Observation of the potential optical counterpart in NGC 4993
  87. LIGO/Virgo G298048: Subaru HSC z-band photometry of the possible optical counterpart
  88. LIGO/Virgo G298048: SkyMapper uvgri photometry of the candidate in NGC 4933
  89. LIGO/Virgo G298048: ATCA detection of a radio source coincident with NGC 4993
  90. LIGO/Virgo G298048: TZAC TAROT Reunion (TRE) observations
  91. LIGO/Virgo G298048: REM optical/NIR observations
  92. LIGO/Virgo G298048: Pan-STARRS detections and izy photometry of the possible optical/NIR counterpart in NGC4993
  93. LIGO/Virgo G298048: Magellan g-band Imaging of the Potential Optical Counterpart Associated with NGC 4993
  94. LIGO/Virgo G298048: Subaru HSC follow-up observations
  95. LIGO/VIRGO G298048: Magellan Optical Spectrum of the Potential Optical Counterpart Associated with NGC 4993
  96. LIGO/Virgo G298048: VLA Detection
  97. LIGO/Virgo G298048: Optical Candidate Shows No Evidence for Previous Activity in Archival SkyMapper Transient Survey Data
  98. LIGO/Virgo G298048: Optical Candidate Shows No Evidence for Previous Activity in Archival ASAS-SN Data
  99. LIGO/Virgo G298048: DLT40 optical candidate
  100. LIGO/Virgo G298048: Potential optical counterpart discovered by Swope telescope

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