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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"

31727 results found.

  1. GRB 240727B: Swift-XRT observations
  2. Fermi GRB 240727A: Global MASTER-Net observations report
  3. GRB 240727A: Swift/UVOT detection
  4. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  5. GRB 240727A: NOT optical observation
  6. GRB 240727A: JinShan optical upper limits
  7. GRB 240727A Bassano Bresciano Observatory upper limit
  8. GRB 240727D: Correction to the GRB name in GCN 36958
  9. GRB 240720B: GRBAlpha detection
  10. GRB 240718A: GRBAlpha detection
  11. GRB 240627A: GRBAlpha detection
  12. Fermi GRB 240726A: Global MASTER-Net observations report
  13. GRB 240727B: Fermi GBM Observation
  14. GRB240529A: VIRT optical transient detection
  15. GRB 240727B: Swift ToO observations
  16. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  17. GRB 240726A: SVOM/GRM observation
  18. GRB240727A: Skynet Optical Afterglow Observations
  19. GRB 240727A: TRT optical afterglow detection
  20. GRB 240727A: KAIT Optical Afterglow Candidate
  21. GRB 240726A: AstroSat CZTI detection of a short burst
  22. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  23. Fermi-LAT gamma-ray observations of IceCube-240725A
  24. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  25. GRB 240720A: Swift-BAT refined analysis
  26. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  27. Fermi-LAT gamma-ray observations of IceCube-240721A
  28. Fermi Gamma-ray Burst Monitor trigger 743243582/240721356 (GRB 240721A) is not a GRB
  29. GRB 240720B: SVOM/GRM observation
  30. Fermi GRB 240720A: Global MASTER-Net observations report
  31. GRB 240720A: AstroSat CZTI detection
  32. GRB 240720A: Fermi GBM observation
  33. Konus-Wind detection of GRB 240718A
  34. GRB 240713A: SVOM/GRM observation
  35. Fermi GRB 240718A: Global MASTER-Net observations report
  36. GRB 240718A: Fermi GBM Observation
  37. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  38. GRB 240718A: Fermi-LAT Detection
  39. GRB 240718A: SVOM/GRM observation
  40. GRB 240712A: Swift-BAT refined analysis
  41. GRB 240716A: GECAM-B detection of a long burst
  42. GRB 240715A: Swift/UVOT observations of the XRT sources.
  43. GRB240713A: Swift/UVOT Upper LImits
  44. EP240708a: X-ray follow-up observations with Swift/XRT
  45. GRB 240715A: GECAM-C detection of a short burst
  46. Konus-Wind detection of GRB 240715A
  47. LIGO/Virgo/KAGRA S240716b: Updated Sky localization
  48. GRB 240713A: Swift-XRT observations
  49. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  50. SVOM/GRM In-Flight Trigger of GRB 240715A
  51. GRB 240713A: LAST optical upper limit
  52. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  53. GRB 240715A: Swift ToO observations
  54. Fermi GRB 240715A: Global MASTER-Net observations report
  55. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  56. GRB 240715A: Fermi GBM Observation
  57. GRB 240712A ATCA radio observations
  58. GRB240715A: GRANDMA Optical Upper Limits
  59. IPN triangulation of GRB 240715A (short)
  60. GRB 240712A: Swift/UVOT Upper Limits
  61. EP-WXT flaring star and the optical flaring activity during its decay phase
  62. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  63. GRB 240713A: Tiled Swift observations
  64. GRB 240713A: J-band upper limit from WINTER
  65. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  66. GRB 240713A: JinShan optical upper limits
  67. GRB 240713A: OHP/T120 optical upper limit
  68. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  69. GRB240713A: X-ray follow-up observation with EP-FXT
  70. GRB240713A: Optical upper limit with Kinder observations
  71. Fermi Sub-threshold Observation of GRB240713A
  72. EP240708a: GSP optical upper limit
  73. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  74. EP240708a: KAIT optical upper limit
  75. Fermi GRB 240710A: Global MASTER-Net observations report
  76. EP240708a: NOT optical observations
  77. EP240708a: SVOM/C-GFT optical upper limit
  78. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  79. EP240708a: Optical upper limits with Kinder observations
  80. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  81. EP240703b: GSP optical upper limit
  82. EP240703b: TRT optical upper limits
  83. EP240703a: TRT further optical observation
  84. EP240702a: TRT optical upper limits
  85. Konus-Wind detection of GRB 240627A
  86. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  87. EP240703a and EP240703b: Swift/XRT upper limits
  88. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  89. EP240703a: KAIT optical upper limit
  90. EP240703a: BTA observations
  91. EP240703c: Kinder optical follow-up and Swift XRT observations
  92. EP240703a: Liverpool Telescope optical follow-up observations
  93. EP240703a/GRB 240703A: TRT optical candidate likely not real
  94. EP240703a: Kinder optical follow-up observations
  95. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  96. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  97. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  98. IPN triangulation of GRB 240627A
  99. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  100. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate

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