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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"

32764 results found.

  1. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  2. GRB 241025A: SVOM/GRM observation
  3. GRB 241025A: TRT optical afterglow observation
  4. Fermi GRB 241024B: Global MASTER-Net observations report
  5. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  6. GRB 241001A: ATCA radio observations
  7. EP241021a: No Detection in Fermi-GBM Observation
  8. GRB 241010A: VIRT Optical Upper Limit
  9. EP241021a: VLT/FORS2 redshift z = 0.75
  10. EP241021a: SAO RAS optical observations
  11. EP241021a: KAIT optical observations
  12. EP241021a: EP-FXT follow-up observation update
  13. IPN triangulation of GRB 241021A (long)
  14. EP241021a: Optical counterpart observations with the Liverpool Telescope
  15. EP241021a: 1.3m DFOT Optical observations
  16. EP241021a: GSP detects optical candidate counterpart
  17. EP241021a: Optical upper limits with Kinder observations
  18. EP241021a: TRT optical observations
  19. GRB 241018A: SVOM/C-GFT optical observations
  20. EP241021a: NOT likely optical counterpart
  21. EP EP241021a: Global MASTER-Net observations report
  22. GRB241017A: 1.3m DFOT optical upper limit
  23. GRB 241018A: 1.3m DFOT Optical upper limit
  24. GRB 241018A: EP-FXT afterglow detection
  25. EP241021a: GOTO optical upper limits
  26. Konus-Wind detection of GRB 241018A
  27. GRB 241018A: SVOM/GRM observation
  28. GRB 241018A/sb24101802: Mephisto optical upper limit
  29. GRB 241017A/sb24101702: Mephisto optical upper limit
  30. GRB 241018A: Mondy optical upper limit
  31. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  32. GRB 241018A: GROWTH-India telescope optical upper limit
  33. GRB241018A: XingLong Optical Upper Limit
  34. GRB 241018A: REM optical/NIR upper limits
  35. GRB 241018A: NOT optical observations
  36. GRB 241017A: SVOM/VT follow-up and optical upper limit
  37. GRB 241018A: SVOM/VT follow-up and optical candidate
  38. GRB 241018A: LCO/0.4m optical upper limits
  39. GRB 241018A: Swift ToO observations
  40. GRB 241006A: VIRT Optical Upper Limit
  41. GRB 240727A: VIRT Optical Upper Limit
  42. GRB 241018A: X-ray afterglow candidate observed by MXT
  43. GRB 241016B: Fermi GBM Observations
  44. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  45. GRB 241001A: EP-FXT afterglow detection
  46. GRB 241017A: GROWTH-India Telescope optical upper limit
  47. GRB241017A: TOO Observations by SVOM/MXT
  48. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  49. GRB 241017A: J-band upper limit from WINTER
  50. GRB 241016B: SVOM/GRM observation
  51. GRB 241017A: Swift ToO observations
  52. Fermi GRB 241016B: Global MASTER-Net observations report
  53. Fermi GRB 241016A: Global MASTER-Net observations report
  54. GRB 241010A: Swift-BAT refined analysis
  55. GRB 241013B: Fermi GBM Observation
  56. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  57. GRB 241013A: Fermi GBM Observation
  58. GRB 240916A: radio detection with the VLA
  59. GRB241013A: REM observations
  60. GRB 241009A: LCO optical upper limits
  61. GRB 241013B: SVOM/GRM observation
  62. Fermi GRB 241013B: Global MASTER-Net observations report
  63. GRB 241013A: a long GRB detected by INTEGRAL
  64. LIGO/Virgo/KAGRA S241009em: Updated Sky localization
  65. LIGO/Virgo/KAGRA S241011k: Updated Sky localization
  66. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  67. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  68. GRB 241009A: GRANDMA optical upper limits
  69. GRB 241010A: JinShan optical observations and potential host galaxy
  70. GRB 241006A: ATCA Radio Upper Limits
  71. LIGO/Virgo/KAGRA S241007bw: Updated Sky localization
  72. Swift GRB 241010A: Global MASTER-Net observations report
  73. GRB 241010A: J-band observations with WINTER
  74. LIGO/Virgo/KAGRA S241009an: Updated Sky localization
  75. Fermi GRB 241010B: Global MASTER-Net observations report
  76. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  77. GRB 241010A: LCO optical observations
  78. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  79. GRB 241006A: Swift-BAT refined analysis
  80. GRB 241009A: Swift ToO observations
  81. LIGO/Virgo/KAGRA S241009l: Updated Sky localization
  82. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  83. GRB 241008A: Fermi GBM Observation
  84. GRB 241008A: Fermi-LAT detection
  85. GRB 241002B: Swift-XRT afterglow detection
  86. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  87. GRB 241002A: NOT optical upper limits
  88. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  89. Fermi GRB 241008A: Global MASTER-Net observations report
  90. IceCube-241006A: No candidates from the Zwicky Transient Facility
  91. GRB 241006A: GRANDMA optical upper limits
  92. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  93. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  94. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  95. GRB 240910A: LBT optical observations
  96. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  97. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  98. GRB 241006A: PRIME near-infrared upper limits
  99. GRB 241006A: Swift/UVOT Upper Limits
  100. GRB 241006A: SVOM/VT follow-up and optical upper limit

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