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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"

32509 results found.

  1. GRB 240727A: TRT optical afterglow detection
  2. GRB 240727A: KAIT Optical Afterglow Candidate
  3. GRB 240726A: AstroSat CZTI detection of a short burst
  4. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  5. Fermi-LAT gamma-ray observations of IceCube-240725A
  6. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  7. GRB 240720A: Swift-BAT refined analysis
  8. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  9. Fermi-LAT gamma-ray observations of IceCube-240721A
  10. Fermi Gamma-ray Burst Monitor trigger 743243582/240721356 (GRB 240721A) is not a GRB
  11. GRB 240720B: SVOM/GRM observation
  12. Fermi GRB 240720A: Global MASTER-Net observations report
  13. GRB 240720A: AstroSat CZTI detection
  14. GRB 240720A: Fermi GBM observation
  15. Konus-Wind detection of GRB 240718A
  16. GRB 240713A: SVOM/GRM observation
  17. Fermi GRB 240718A: Global MASTER-Net observations report
  18. GRB 240718A: Fermi GBM Observation
  19. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  20. GRB 240718A: Fermi-LAT Detection
  21. GRB 240718A: SVOM/GRM observation
  22. GRB 240712A: Swift-BAT refined analysis
  23. GRB 240716A: GECAM-B detection of a long burst
  24. GRB 240715A: Swift/UVOT observations of the XRT sources.
  25. GRB240713A: Swift/UVOT Upper LImits
  26. EP240708a: X-ray follow-up observations with Swift/XRT
  27. GRB 240715A: GECAM-C detection of a short burst
  28. Konus-Wind detection of GRB 240715A
  29. LIGO/Virgo/KAGRA S240716b: Updated Sky localization
  30. GRB 240713A: Swift-XRT observations
  31. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  32. SVOM/GRM In-Flight Trigger of GRB 240715A
  33. GRB 240713A: LAST optical upper limit
  34. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  35. GRB 240715A: Swift ToO observations
  36. Fermi GRB 240715A: Global MASTER-Net observations report
  37. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  38. GRB 240715A: Fermi GBM Observation
  39. GRB 240712A ATCA radio observations
  40. GRB240715A: GRANDMA Optical Upper Limits
  41. IPN triangulation of GRB 240715A (short)
  42. GRB 240712A: Swift/UVOT Upper Limits
  43. EP-WXT flaring star and the optical flaring activity during its decay phase
  44. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  45. GRB 240713A: Tiled Swift observations
  46. GRB 240713A: J-band upper limit from WINTER
  47. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  48. GRB 240713A: JinShan optical upper limits
  49. GRB 240713A: OHP/T120 optical upper limit
  50. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  51. GRB240713A: X-ray follow-up observation with EP-FXT
  52. GRB240713A: Optical upper limit with Kinder observations
  53. Fermi Sub-threshold Observation of GRB240713A
  54. EP240708a: GSP optical upper limit
  55. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  56. EP240708a: KAIT optical upper limit
  57. Fermi GRB 240710A: Global MASTER-Net observations report
  58. EP240708a: NOT optical observations
  59. EP240708a: SVOM/C-GFT optical upper limit
  60. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  61. EP240708a: Optical upper limits with Kinder observations
  62. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  63. EP240703b: GSP optical upper limit
  64. EP240703b: TRT optical upper limits
  65. EP240703a: TRT further optical observation
  66. EP240702a: TRT optical upper limits
  67. Konus-Wind detection of GRB 240627A
  68. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  69. EP240703a and EP240703b: Swift/XRT upper limits
  70. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  71. EP240703a: KAIT optical upper limit
  72. EP240703a: BTA observations
  73. EP240703c: Kinder optical follow-up and Swift XRT observations
  74. EP240703a: Liverpool Telescope optical follow-up observations
  75. EP240703a/GRB 240703A: TRT optical candidate likely not real
  76. EP240703a: Kinder optical follow-up observations
  77. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  78. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  79. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  80. IPN triangulation of GRB 240627A
  81. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  82. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  83. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  84. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  85. EP240702a: Swift/XRT upper limit
  86. EP240702a: GSP optical upper limit
  87. Fermi GRB 240702A: Global MASTER-Net observations report
  88. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  89. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  90. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  91. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  92. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  93. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  94. Fermi GRB 240629A: Global MASTER-Net observations report
  95. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  96. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  97. IPN triangulation of GRB 240619C
  98. GRB 240627A: NuSTAR Detection of the long GRB
  99. GRB 240615A: SAI CMO J- band observations
  100. EP240626a: Montarrenti Observatory optical upper limit

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