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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

5817 results found.

  1. GRB 241025C: VZLUSAT-2 detection
  2. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  3. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  4. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  5. Fermi trigger No 752878030: Global MASTER-Net observations report
  6. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  7. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  8. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  9. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  10. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  12. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  13. GRB 240511A: LCO upper limits
  14. Fermi GRB 241105A: Global MASTER-Net observations report
  15. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  16. EP241103a: Global MASTER-Net observations report
  17. EP241101a: Global MASTER-Net observations report
  18. Fermi trigger No 752083996: Global MASTER-Net observations report
  19. GRB 241029A: LCO optical detection
  20. Fermi trigger No 752006065: Global MASTER-Net observations report
  21. EP241021a: Swift-UVOT detection
  22. EP241021a: Optical rebrightening observations with Mephisto
  23. GRB 241030A : MITSuME Akeno optical afterglow detection
  24. GRB 241029A: GOTO optical afterglow detection
  25. GRB 241029A: MASTER early optical counterpart detection
  26. GRB 241029A: TRT optical afterglow candidate detection
  27. EP 241026b: LBT optical observations
  28. GRB 241026A: SAO RAS observations of possible optical afterglow
  29. Fermi trigger No 751554401: Global MASTER-Net observations report
  30. Fermi trigger No 751449953: Global MASTER-Net observations report
  31. EP241021a: TRT optical observations
  32. GRB 241009A: LCO optical upper limits
  33. GRB 241006A: ATCA Radio Upper Limits
  34. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  37. Fermi GRB 241008A: Global MASTER-Net observations report
  38. IceCube-241006A: No candidates from the Zwicky Transient Facility
  39. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  40. GRB 240910A: LBT optical observations
  41. Fermi trigger No 749721670: Global MASTER-Net observations report
  42. GRB 240930B / EP 240930a: SVOM/GRM observation
  43. Fermi trigger No 749735279: Global MASTER-Net observations report
  44. Fermi trigger No 749630753: Global MASTER-Net observations report
  45. Fermi trigger No 749693019: Global MASTER-Net observations report
  46. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  47. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  48. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  49. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  50. GRB 241002B: GOTO optical counterpart candidate
  51. GRB 240930B: GRBAlpha detection
  52. GRB 240929A: GRBAlpha detection
  53. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  54. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  55. EP240930a: GOTO optical upper limits
  56. GRB 240929A: SVOM/GRM observation
  57. EP EP240930a: Global MASTER-Net observations report
  58. EP240930a: EP-WXT detection of a fast X-ray transient
  59. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  60. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  61. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  62. AMON NuEM 240926A: Swift XRT Follow-up
  63. GRB 240929A : Leavitt Observatory optical upper limit
  64. Fermi GRB 240930B: Global MASTER-Net observations report
  65. GRB 240825A: LBT optical observations
  66. GRB 240928A: SVOM/GRM observation
  67. Fermi GRB 240930A: Global MASTER-Net observations report
  68. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  69. Fermi trigger No 749339671: Global MASTER-Net observations report
  70. Fermi GRB 240929A: Global MASTER-Net observations report
  71. Integral GRB240929.83: Global MASTER-Net observations report
  72. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  73. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  74. GRB 240926A: SVOM/GRM observation
  75. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  76. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240926A
  77. EP240919a / GRB 240919A: SVOM/VT upper limit
  78. EP240918b and EP240918c: EP-FXT follow-up observations
  79. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  80. GRB 240905B: VZLUSAT-2 detection
  81. EP trigger ID 01709059262: correction to the observation start time and source localization
  82. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  83. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  84. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo S240919bn: GOTO optical upper limits
  86. GRB 240918B: AstroSat CZTI detection
  87. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  89. EP240919a: EP-FXT follow-up observation update
  90. EP240913A/GRB 240913C: AbAO optical upper limit
  91. EP240919a / GRB 240919A: Mondy optical upper limit
  92. EP240913a/GRB 240913C: 1.6m Mephisto observations
  93. EP240918a: SVOM/VT upper limit
  94. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  95. GRB 240919A / EP240919a: SVOM/GRM observation
  96. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  97. EP EP240919a: Global MASTER-Net observations report
  98. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  99. EP240919a: NOT and Gemini optical observations
  100. EP240919a: GOTO optical upper limits

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