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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 241018A: SVOM/VT follow-up and optical candidate
  2. GRB 241018A: LCO/0.4m optical upper limits
  3. GRB 241018A: Swift ToO observations
  4. GRB 241006A: VIRT Optical Upper Limit
  5. GRB 240727A: VIRT Optical Upper Limit
  6. GRB 241018A: X-ray afterglow candidate observed by MXT
  7. GRB 241016B: Fermi GBM Observations
  8. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  9. GRB 241001A: EP-FXT afterglow detection
  10. GRB 241017A: GROWTH-India Telescope optical upper limit
  11. GRB241017A: TOO Observations by SVOM/MXT
  12. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  13. GRB 241017A: J-band upper limit from WINTER
  14. GRB 241016B: SVOM/GRM observation
  15. GRB 241017A: Swift ToO observations
  16. Fermi GRB 241016B: Global MASTER-Net observations report
  17. Fermi GRB 241016A: Global MASTER-Net observations report
  18. GRB 241010A: Swift-BAT refined analysis
  19. GRB 241013B: Fermi GBM Observation
  20. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  21. GRB 241013A: Fermi GBM Observation
  22. GRB 240916A: radio detection with the VLA
  23. GRB241013A: REM observations
  24. GRB 241009A: LCO optical upper limits
  25. GRB 241013B: SVOM/GRM observation
  26. Fermi GRB 241013B: Global MASTER-Net observations report
  27. GRB 241013A: a long GRB detected by INTEGRAL
  28. LIGO/Virgo/KAGRA S241009em: Updated Sky localization
  29. LIGO/Virgo/KAGRA S241011k: Updated Sky localization
  30. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  31. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  32. GRB 241009A: GRANDMA optical upper limits
  33. GRB 241010A: JinShan optical observations and potential host galaxy
  34. GRB 241006A: ATCA Radio Upper Limits
  35. LIGO/Virgo/KAGRA S241007bw: Updated Sky localization
  36. Swift GRB 241010A: Global MASTER-Net observations report
  37. GRB 241010A: J-band observations with WINTER
  38. LIGO/Virgo/KAGRA S241009an: Updated Sky localization
  39. Fermi GRB 241010B: Global MASTER-Net observations report
  40. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  41. GRB 241010A: LCO optical observations
  42. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  43. GRB 241006A: Swift-BAT refined analysis
  44. GRB 241009A: Swift ToO observations
  45. LIGO/Virgo/KAGRA S241009l: Updated Sky localization
  46. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  47. GRB 241008A: Fermi GBM Observation
  48. GRB 241008A: Fermi-LAT detection
  49. GRB 241002B: Swift-XRT afterglow detection
  50. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  51. GRB 241002A: NOT optical upper limits
  52. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  53. Fermi GRB 241008A: Global MASTER-Net observations report
  54. IceCube-241006A: No candidates from the Zwicky Transient Facility
  55. GRB 241006A: GRANDMA optical upper limits
  56. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  57. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  58. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  59. GRB 240910A: LBT optical observations
  60. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  61. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  62. GRB 241006A: PRIME near-infrared upper limits
  63. GRB 241006A: Swift/UVOT Upper Limits
  64. GRB 241006A: SVOM/VT follow-up and optical upper limit
  65. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  66. GRB 240930B: SVOM/C-GFT optical upper limit
  67. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  68. GRB 240930B / EP 240930a: SVOM/GRM observation
  69. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  70. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  71. GRB 241002B: Fermi GBM Observation
  72. GRB 241002B: Swift-XRT observations
  73. GRB 241002C: SVOM/C-GFT optical upper limit
  74. GRB 241002A: Swift-BAT refined analysis
  75. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  76. GRB 241002B: Swift ToO observations
  77. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  78. Konus-Wind detection of GRB 240926A
  79. GRB 241002B: PRIME near-infrared detection
  80. GRB 241002C: Swift ToO observations
  81. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  82. IPN triangulation of GRB 240930B / EP 240930a
  83. GRB 241001A : SVOM/VT optical detection
  84. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  85. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  86. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  87. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  88. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  89. GRB 241002C : MITSuME Akeno optical upper limits
  90. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  91. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  92. GRB241001A: REM optical/NIR upper limits
  93. LIGO/Virgo/KAGRA S241002e: Updated Sky localization
  94. GRB 241002A: Swift/UVOT Upper Limits
  95. EP240930a: Liverpool Telescope observations
  96. GRB 241002A: LCOGT Optical Upper Limits
  97. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  98. GRB 241001A: Swift/UVOT Detection
  99. GRB 241001A: VLT/X-shooter redshift
  100. GRB 241002B: GOTO optical counterpart candidate

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