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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"

31634 results found.

  1. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  2. GRB 241018A: GROWTH-India telescope optical upper limit
  3. GRB241018A: XingLong Optical Upper Limit
  4. GRB 241018A: REM optical/NIR upper limits
  5. GRB 241018A: NOT optical observations
  6. GRB 241017A: SVOM/VT follow-up and optical upper limit
  7. GRB 241018A: SVOM/VT follow-up and optical candidate
  8. GRB 241018A: LCO/0.4m optical upper limits
  9. GRB 241018A: Swift ToO observations
  10. GRB 241006A: VIRT Optical Upper Limit
  11. GRB 240727A: VIRT Optical Upper Limit
  12. GRB 241018A: X-ray afterglow candidate observed by MXT
  13. GRB 241016B: Fermi GBM Observations
  14. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  15. GRB 241001A: EP-FXT afterglow detection
  16. GRB 241017A: GROWTH-India Telescope optical upper limit
  17. GRB241017A: TOO Observations by SVOM/MXT
  18. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  19. GRB 241017A: J-band upper limit from WINTER
  20. GRB 241016B: SVOM/GRM observation
  21. GRB 241017A: Swift ToO observations
  22. Fermi GRB 241016B: Global MASTER-Net observations report
  23. Fermi GRB 241016A: Global MASTER-Net observations report
  24. GRB 241010A: Swift-BAT refined analysis
  25. GRB 241013B: Fermi GBM Observation
  26. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  27. GRB 241013A: Fermi GBM Observation
  28. GRB 240916A: radio detection with the VLA
  29. GRB241013A: REM observations
  30. GRB 241009A: LCO optical upper limits
  31. GRB 241013B: SVOM/GRM observation
  32. Fermi GRB 241013B: Global MASTER-Net observations report
  33. GRB 241013A: a long GRB detected by INTEGRAL
  34. LIGO/Virgo/KAGRA S241009em: Updated Sky localization
  35. LIGO/Virgo/KAGRA S241011k: Updated Sky localization
  36. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  37. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  38. GRB 241009A: GRANDMA optical upper limits
  39. GRB 241010A: JinShan optical observations and potential host galaxy
  40. GRB 241006A: ATCA Radio Upper Limits
  41. LIGO/Virgo/KAGRA S241007bw: Updated Sky localization
  42. Swift GRB 241010A: Global MASTER-Net observations report
  43. GRB 241010A: J-band observations with WINTER
  44. LIGO/Virgo/KAGRA S241009an: Updated Sky localization
  45. Fermi GRB 241010B: Global MASTER-Net observations report
  46. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  47. GRB 241010A: LCO optical observations
  48. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  49. GRB 241006A: Swift-BAT refined analysis
  50. GRB 241009A: Swift ToO observations
  51. LIGO/Virgo/KAGRA S241009l: Updated Sky localization
  52. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  53. GRB 241008A: Fermi GBM Observation
  54. GRB 241008A: Fermi-LAT detection
  55. GRB 241002B: Swift-XRT afterglow detection
  56. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  57. GRB 241002A: NOT optical upper limits
  58. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  59. Fermi GRB 241008A: Global MASTER-Net observations report
  60. IceCube-241006A: No candidates from the Zwicky Transient Facility
  61. GRB 241006A: GRANDMA optical upper limits
  62. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  63. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  64. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  65. GRB 240910A: LBT optical observations
  66. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  67. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  68. GRB 241006A: PRIME near-infrared upper limits
  69. GRB 241006A: Swift/UVOT Upper Limits
  70. GRB 241006A: SVOM/VT follow-up and optical upper limit
  71. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  72. GRB 240930B: SVOM/C-GFT optical upper limit
  73. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  74. GRB 240930B / EP 240930a: SVOM/GRM observation
  75. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  76. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  77. GRB 241002B: Fermi GBM Observation
  78. GRB 241002B: Swift-XRT observations
  79. GRB 241002C: SVOM/C-GFT optical upper limit
  80. GRB 241002A: Swift-BAT refined analysis
  81. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  82. GRB 241002B: Swift ToO observations
  83. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  84. Konus-Wind detection of GRB 240926A
  85. GRB 241002B: PRIME near-infrared detection
  86. GRB 241002C: Swift ToO observations
  87. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  88. IPN triangulation of GRB 240930B / EP 240930a
  89. GRB 241001A : SVOM/VT optical detection
  90. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  91. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  92. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  93. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  94. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  95. GRB 241002C : MITSuME Akeno optical upper limits
  96. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  97. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  98. GRB241001A: REM optical/NIR upper limits
  99. LIGO/Virgo/KAGRA S241002e: Updated Sky localization
  100. GRB 241002A: Swift/UVOT Upper Limits

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