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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"

4067 results found.

  1. LIGO/Virgo S230611l: Global MASTER-Net observations report
  2. LIGO/Virgo/KAGRA S230609u: Updated Sky localization
  3. LIGO/Virgo S230609u: Global MASTER-Net observations report
  4. LIGO/Virgo S230608aw: Global MASTER-Net observations report
  5. LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
  6. LIGO/Virgo S230608as: Global MASTER-Net observations report
  7. LIGO/Virgo S230609a: Global MASTER-Net observations report
  8. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  9. LIGO/Virgo S230608q: Global MASTER-Net observations report
  10. LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo/KAGRA S230602ap: Zwicky Transient Facility observations
  12. LIGO/Virgo S230606z: Global MASTER-Net observations report
  13. LIGO/Virgo S230606d: Global MASTER-Net observations report
  14. LIGO/Virgo/KAGRA S230606d: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo/KAGRA S230605o: Updated Sky localization
  16. IceCube-230603A: Upper limits from a search for additional neutrino events in IceCube
  17. LIGO/Virgo/KAGRA S230601bf: Updated Sky localization
  18. LIGO/Virgo/KAGRA S230605o: Identification of a GW compact binary merger candidate
  19. LIGO/Virgo S230605o: Global MASTER-Net observations report
  20. LIGO/Virgo S230604z: Global MASTER-Net observations report
  21. LIGO/Virgo S230603aa: Global MASTER-Net observations report
  22. LIGO/Virgo S230602ap: Global MASTER-Net observations report
  23. LIGO/Virgo/KAGRA S230518h: Upper limits from a two-week IceCube neutrino search
  24. LIGO/Virgo S230601bf: Global MASTER-Net observations report
  25. LIGO/Virgo/KAGRA S230601bf: Identification of a GW compact binary merger candidate
  26. LIGO/Virgo S230531f: Global MASTER-Net observations report
  27. LIGO/Virgo/KAGRA S230529ay: Zwicky Transient Facility observations
  28. LIGO/Virgo/KAGRA S230528a: Zwicky Transient Facility observations
  29. LIGO/Virgo/KAGRA S230527ch: Zwicky Transient Facility observations
  30. LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
  31. LIGO/Virgo/KAGRA S230529ay: AstroSat CZTI non-detection and upper limits
  32. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S230529ay: upper limits from AGILE/MCAL
  34. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  35. LIGO/Virgo/KAGRA S230529ay: Upper limits from Fermi-GBM Observations
  36. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  37. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  38. LIGO/Virgo/KAGRA S230529ay: Identification of a GW compact binary merger candidate
  39. LIGO/Virgo S230529p: Global MASTER-Net observations report
  40. LIGO/Virgo S230525a: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S230518h: Updated Sky localization
  42. LIGO/Virgo/KAGRA S230520ae: Updated Sky localization
  43. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  44. LIGO/Virgo/KAGRA S230518h: TESS observations of the localization region
  45. LIGO/Virgo/KAGRA S230518h: No transient candidates in CALET observations
  46. LIGO/Virgo/KAGRA S230524x: Retraction of GW compact binary merger candidate
  47. LIGO/Virgo S230524b: Global MASTER-Net observations report
  48. LIGO/Virgo/KAGRA S230521k: MASTER new OT discovery
  49. LIGO/Virgo/KAGRA S230521k: Additional candidates from Zwicky Transient Facility
  50. LIGO/Virgo S230522n: Global MASTER-Net observations report
  51. LIGO/Virgo S230522a: Global MASTER-Net observations report
  52. LIGO/Virgo/KAGRA S230522n: Upper limits from IceCube neutrino search
  53. LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for MeerLICHT candidates: AT2023ixg and AT2023iyb
  54. LIGO/Virgo/KAGRA S230522a: 2 counterpart neutrino candidates from IceCube neutrino searches
  55. LIGO/Virgo S230521k: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S230521k: Zwicky Transient Facility observations
  57. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  58. LIGO/Virgo/KAGRA S230520ae: Identification of a GW compact binary merger candidate: End-to-End Test
  59. LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
  60. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  61. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  62. LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for Swope candidates: SSS23a, SSS23b and SSS23c
  63. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  64. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  65. LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
  66. LIGO/Virgo S230518h: AGILE/MCAL observations
  67. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  68. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  69. LIGO/Virgo/Kagra S230518h: NED Galaxies in the Localization Volume
  70. LIGO/Virgo/KAGRA S230518h: AstroSat CZTI non-detection and upper limits
  71. LIGO/Virgo/KAGRA S230518h: Upper limits from Fermi-GBM Observations
  72. LIGO/Virgo S230518h: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S230518h: Updated Sky localization and EM Bright Classification
  74. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  75. LIGO/Virgo S230518h: Upper limits from IceCube neutrino search
  76. LIGO/Virgo/KAGRA S230518h: Identification of a GW compact binary merger candidate
  77. IceCube-230511A: Upper limits from a search for additional neutrino events in IceCube
  78. IceCube-230506A: Upper limits from a search for additional neutrino events in IceCube
  79. GRB 230423A: Swift/UVOT Upper Limits
  80. New GCN Circulars Portal for Rapid Communications on Astronomical Transients is Online
  81. GRB 221231A: Swift/BAT-GUANO arcminute localization of a possibly short burst
  82. GRB 221215A: Swift/BAT-GUANO arcminute localization
  83. GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
  84. LIGO-Virgo-KAGRA and GEO600 statement on GRB 221009A
  85. IPN triangulation of GRB 220927A (long)
  86. GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
  87. IPN triangulation of GRB 220903A (long)
  88. GRB 220831A: Swift/BAT-GUANO localization of a short burst
  89. Introducing new GCN Kafka broker and web site for transient alerts, https://gcn.nasa.gov
  90. GRB 220710A: Swift/BAT-GUANO arcminute localization
  91. IPN triangulation of GRB 220711C (short)
  92. GRB 220708B: Swift/BAT-GUANO arcminute localization
  93. GRB 220606B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  94. IPN triangulation of GRB 220601A (long)
  95. Fermi-GBM will trial new SAA regions from Tuesday June 7th
  96. IPN triangulation of GRB 220524B
  97. IPN triangulation of GRB 220524A
  98. IPN triangulation of GRB 220521B
  99. IPN triangulation of GRB 220519A
  100. GRB 220514A: MITSuME Akeno optical observation

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Download all Circulars as a .tar.gz archive (updated once a day):
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