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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"

2707 results found.

  1. LIGO/Virgo G275697: AMI Large Array Search for a Radio Afterglow
  2. IceCube-170321A - IceCube observation of a high-energy neutrino candidate event
  3. IceCube-170312A: MASTER follow-up observations
  4. LIGO/Virgo G277583: ATLAS17cck - a fast declining transient
  5. LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
  6. LIGO/Virgo G275404: Medicina radio follow-up of near-infrared
  7. LIGO/Virgo G270580: optical observations and classification of PS and MASTER sources
  8. SN MASTER OT J042250.16-820415.4 is the possible optical counterpart of the gravitational waves event LIGO/Virgo G274296
  9. GRB170306A: SALT observations
  10. LIGO/Virgo G275404 and AGL J1914+1043: INTEGRAL follow-up
  11. Swift Trigger 741528: a possible GRB
  12. LIGO/Virgo G275697: Additional iPTF Optical Transient Candidates
  13. LIGO/Virgo G274296 and G275404 : MAXI/GSC observations
  14. LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
  15. LIGO/Virgo G275697: INTEGRAL search for a prompt gamma-ray counterpart
  16. LIGO/Virgo G275404: Fermi-LAT search for a high-energy gamma-ray counterpart
  17. LIGO/Virgo G275404: INTEGRAL search for a prompt gamma-ray counterpart
  18. LIGO/Virgo G275404: AGILE-GRID detection of a possible gamma-ray transient
  19. LIGO/Virgo G274296: MASTER new bright possible SN detection and inspection dinamic
  20. LIGO/Virgo G274296: Fermi-LAT search for a high-energy gamma-ray counterpart
  21. LIGO/Virgo G274296: Pan-STARRS imaging and discovery of 70 transients
  22. LIGO/Virgo G274296: INTEGRAL search for a prompt gamma-ray counterpart
  23. Fermi Trigger 508295323: MASTER-OAFA possible OT detection
  24. GRB 170208B: GROND observations
  25. GRB 170205A: Swift-BAT refined analysis
  26. LIGO/Virgo G268556: FLOYDS Spectrum of iPTF17cf/PS17fr Favors an AGN Classification
  27. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  28. GRB 170121B: AbAO optical observations
  29. GRB 170121B: MASTER early optical observations of the Swift possible XT
  30. GRB 170121B: Swift-XRT and UVOT observations
  31. LIGO/Virgo G270580: Fermi-LAT search for a high-energy gamma-ray counterpart
  32. LIGO/Virgo G270580: INTEGRAL search of temporally coincident prompt hard X-ray
  33. LIGO/Virgo G268556: Global MASTER Net 21 OTs detection
  34. Swift Trigger #733426: possible detection of a burst or transient
  35. LIGO/Virgo G268556: spectra of two nuclear transients PS17fr and PS17er
  36. LIGO/Virgo G268556: Gemini spectra of Pan-STARRS1 transients
  37. LIGO/Virgo G268556: Liverpool Telescope Spectroscopy of iPTF17bv and iPTF17ck
  38. GRB170105A: AstroSat CZTI localisation
  39. LIGO/Virgo G268556: Palomar 200-inch detects ATLAS17aeu, possible afterglow of GRB070105A?
  40. LIGO/Virgo G268556/GW170104: Global MASTER Net observations and first OT detection
  41. LIGO/Virgo G268556: Fermi-LAT search for high-energy gamma-ray counterpart
  42. LIGO/Virgo G268556: Mini-MegaTORTORA follow-up observations
  43. LIGO/Virgo G268556: INTEGRAL search of temporally coincident prompt hard X-ray emission
  44. GMRT radio detection of GRB 161219B
  45. Swift Trigger 728268: a possible GRB
  46. Swift Trigger 728094: a possible GRB
  47. GRB 161218A: Swift-BAT refined analysis
  48. GRB 161214B: Swift/UVOT Observations
  49. GRB 161214B: NOT optical observations, possible counterpart
  50. IceCube-161210: IceCube observation of a high-energy neutrino candidate event
  51. GRB 161129A: TSHAO optical observations / possible afterglow+host galaxy
  52. GRB 161119A: MASTER-SAAO possible OT detection during Fermi Alert
  53. GRB 161104A: Magellan imaging and spectroscopy
  54. GRB 161106A: CALET Gamma-Ray Burst Monitor detection
  55. IceCube-161103: IceCube observation of a very-high-energy neutrino
  56. Radio upper limit on the GRB 161011A with the GMRT
  57. GRB161004A: Further analysis of the burst nature
  58. GRB 161010A: Swift/UVOT Possible Detection
  59. GRB 161007A: Swift/UVOT Upper Limits
  60. GRB 161004A: Swift-BAT refined analysis
  61. GRB 161004A: Swift detection of a burst with a possible optical counterpart
  62. Possible radio detection of GRB 160910A with the GMRT
  63. GRB 160925A: Bassano Bresciano Photometry of MASTER optical transient
  64. GRB 160925A: Optical spectroscopy of MASTER optical transient
  65. GRB 160816A: Possible radio afterglow detection at 15 GHz with AMI
  66. IceCube HESE 160814: MASTER OT J130845.02-323254.9 as the possible source of the high energy neutrino
  67. GRB 160816A, the review of the sky area in plate archives
  68. GRB 160825A: not localized by Swift
  69. GRB 160824A: Swift/UVOT Possible Afterglow Detection
  70. Possible radio detection of GRB160703A with the GMRT
  71. Possible radio detection of GRB160623A with the GMRT
  72. GRB 160821A: Swift-BAT refined analysis
  73. GRB 160816A: MASTER inspection
  74. IceCube 160806A EHE Neutrino Candidate Event
  75. Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
  76. GRB160804A: MASTER-SAAO observation
  77. Global MASTER net follow up of IceCube-160731A
  78. Swift Trigger 704327: KAIT Optical Observations
  79. Swift Trigger 704444 is probably not an astrophysical event.
  80. Swift Trigger 704327: MASTER syncronous optical observations
  81. Swift Trigger 704327: a possible GRB
  82. GRB 160712A: Swift/UVOT Upper Limits
  83. SGR 1935+2154: CALET Gamma-Ray Burst Monitor detections
  84. GRB 160705B: Swift-BAT refined analysis
  85. GRB 160623A: Possible detection of a radio afterglow at 15 GHz with AMI
  86. GRB 160624A: Lulin observation
  87. GRB160624A:possible GRB host redshift
  88. Fermi GBM Trigger 160622573 is not a GRB
  89. BAT trigger 700791 (possible GRB 160622A) is SNR RCW 103
  90. GRB 160622A: Swift detection of a possible short GRB or a new SGR
  91. Trigger 689956: Swift detection of a source near the Galactic center
  92. Trigger 689353 (possible transient near Sgr A*), Swift-BAT refined analysis
  93. GRB 160530A: discovery with the Compton Spectrometer and Imager
  94. GRB 160525A: Swift-BAT refined analysis
  95. GRB 160521B: Theoretical estimate of the redshift and urgent need for further x-ray observations
  96. GRB 160425A: SMARTS late-time observations
  97. GRB 160521B: Swift/UVOT Upper Limits
  98. Fermi GBM triggers of SGR 1935+2154
  99. Interplanetary Network Search for IceCube 160427A
  100. GRB 160509A Gemini North redshift

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