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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"

32540 results found.

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

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