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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').
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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"

32544 results found.

  1. GRB 230709C: Fermi GBM Detection
  2. GRB 230707B: Fermi GBM Observation
  3. LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
  4. LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate
  5. IceCube-230707A: No candidates detected by Swift-XRT
  6. Swift Trigger 1178410 is not an astrophysical event
  7. GRB 230709C: AstroSat CZTI detection
  8. LIGO/Virgo/KAGRA S230708cf: Updated Sky localization
  9. GRB 230707B: CALET Gamma-Ray Burst Monitor detection
  10. GRB 230703A detected with multiple GRID detectors
  11. LIGO/Virgo/KAGRA S230707ai: Updated Sky localization
  12. IceCube-230707A: No candidates from the Zwicky Transient Facility
  13. Fermi-LAT gamma-ray observations of IceCube-230708A
  14. Fermi-LAT gamma-ray observations of IceCube-230707B
  15. Fermi-LAT gamma-ray observations of IceCube-230707A
  16. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  17. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  18. IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
  19. IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
  20. IceCube-230707A: Upper limits from a search for additional neutrino events in IceCube
  21. LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate
  22. LIGO/Virgo/KAGRA S230708cf: Identification of a GW compact binary merger candidate
  23. GRB 230628C: GRID Detection
  24. GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  25. GRB 230707A: Fermi GBM Detection
  26. LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
  27. GRB 230707A: Swift ToO observations
  28. GRB 230707A: Swift/BAT-GUANO arcminute localization of a burst
  29. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  30. Fermi GRB 230707A: Global MASTER-Net observations report
  31. LIGO/Virgo/KAGRA S230706ah: Updated Sky localization
  32. LIGO/Virgo/KAGRA S230704f: Updated Sky localization
  33. LIGO/Virgo/KAGRA S230630bq: Updated Sky localization
  34. LIGO/Virgo/KAGRA S230702an: Updated Sky localization
  35. GRB 230625A: Detection by GRID
  36. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  37. LIGO/Virgo/KAGRA S230706ah: Identification of a GW compact binary merger candidate
  38. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  39. ZTF23aaoohpy/AT2023lcr: AMI-LA radio detection
  40. GRB 230626A: VZLUSAT-2 detection
  41. LVK S230619bd/GBM-230619: Upper limits from a two-week IceCube neutrino search
  42. GRB 230328B: LBT detection of the likely host galaxy
  43. LIGO/Virgo/KAGRA S230704f: Identification of a GW compact binary merger candidate
  44. Konus-Wind detection of GRB 220623A
  45. LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
  46. LIGO/Virgo/KAGRA S230702an: Identification of a GW compact binary merger candidate
  47. GRB 230628E: Swift/UVOT Detection
  48. GRB 230628E: Swift-BAT refined analysis
  49. GRB 230628E: ATCA rapid radio follow-up
  50. LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates
  51. LIGO/Virgo/KAGRA S230630bq: Identification of a GW compact binary merger candidate
  52. IPN triangulation of GRB 230625B (ultra-long)
  53. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
  54. LIGO/Virgo/KAGRA S230630am: Identification of a GW compact binary merger candidate
  55. GRB 230625B: CALET Gamma-Ray Burst Monitor detection
  56. GRB 230628E - VLT spectroscopic observations
  57. ZTF23aaoohpy/AT2023lcr: LBT observations
  58. Fermi GRB 230628C: Global MASTER-Net observations report
  59. GRB 230625B: AstroSat CZTI detection
  60. GRB230628E: VLT optical identification of afterglow candidate
  61. GRB 230628E: Enhanced Swift-XRT position (Correction to name in GCN 34115)
  62. Fermi GRB 230628D: Global MASTER-Net observations report
  63. LIGO/Virgo/KAGRA S230628ax: Identification of a GW compact binary merger candidate
  64. GRB 230628E: LCOGT Optical Upper Limit
  65. GRB 230623B: CALET Gamma-Ray Burst Monitor detection
  66. LIGO/Virgo/KAGRA S230516az: GOTO candidate counterpart GOTO23hu ruled out by Zwicky Transient Facility observations
  67. ZTF23aaoohpy /AT2023lcr: TNG NIR detection
  68. LIGO/Virgo/KAGRA S230627c: Additional observations from the Zwicky Transient Facility
  69. GRB 230626A: GRBAlpha detection
  70. AT2023lcr: JCMT SCUBA-2 sub-mm observations
  71. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  72. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  73. LIGO/Virgo/KAGRA S230627c: Upper limits from Fermi-GBM Observations
  74. Konus-Wind detection of GRB 230616A
  75. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  76. LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
  77. LIGO/Virgo/KAGRA S230627c: Updated Sky localization and EM Bright Classification
  78. LIGO/Virgo/KAGRA S230627c: Identification of a GW compact binary merger candidate
  79. GRB 230618A: Swift-BAT refined analysis
  80. LIGO/Virgo/KAGRA S230624av: Updated Sky localization
  81. GRB 230622A: Swift-BAT refined analysis
  82. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  83. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  84. ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
  85. LIGO/Virgo/KAGRA S230624av: Identification of a GW compact binary merger candidate
  86. GRB 230623A: Tiled Swift observations
  87. MAXI GRB 230623A: MASTER optical observations
  88. GRB 230623A: Tiled Swift observations
  89. GRB 230622A: ATCA rapid radio follow-up
  90. Swift GRB 230622A: Global MASTER-Net observations report
  91. LIGO/Virgo/KAGRA S230615az: LBT spectroscopic classification of GOTO23hn
  92. LIGO/Virgo/KAGRA S230615az: LBT spectroscopic redshift of the host galaxy of GOTO23hn
  93. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  94. Fermi GBM-230619: AstroSat CZTI non-detection and upper limits for the sub-threshold candidate
  95. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  96. AT2023lcr: VLA radio detection
  97. ZTF23aaoohpy/AT2023lcr: Montarrenti Observatory optical observations
  98. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
  99. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  100. ZTF23aaoohpy/AT2023lc: Mondy optical observations

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