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J/ApJ/716/L109   Radio and X-ray observations of Aql X-1   (Miller-Jones+, 2010)

Evolution of the Radio-X-ray coupling throughout an entire outburst of Aquila X-1. Miller-Jones J.C.A., Sivakoff G.R., Altamirano D., Tudose V., Migliari S., Dhawan V., Fender R.P., Garrett M.A., Heinz S., Kording E.G., Krimm H.A., Linares M., Maitra D., Markoff S., Paragi Z., Remillard R.A., Rupen M.P., Rushton A., Russell D.M., Sarazin C.L., Spencer R.E. <Astrophys. J., 716, L109-L114 (2010)> =2010ApJ...716L.109M
ADC_Keywords: Binaries, X-ray ; Radio continuum ; Pulsars Keywords: astrometry - radio continuum: stars - stars: individual (Aql X-1) - X-rays: binaries Abstract: The 2009 November outburst of the neutron star X-ray binary Aquila X-1 (Aql X-1) was observed with unprecedented radio coverage and simultaneous pointed X-ray observations, tracing the radio emission around the full X-ray hysteresis loop of the outburst for the first time. We use these data to discuss the disk-jet coupling, finding the radio emission to be consistent with being triggered at state transitions, both from the hard to the soft spectral state and vice versa. Our data appear to confirm previous suggestions of radio quenching in the soft state above a threshold X-ray luminosity of ∼10% of the Eddington luminosity. We also present the first detections of Aql X-1 with very long baseline interferometry, showing that any extended emission is relatively diffuse and consistent with steady jets rather than arising from discrete, compact knots. In all cases where multi-frequency data were available, the source radio spectrum is consistent with being flat or slightly inverted, suggesting that the internal shock mechanism that is believed to produce optically thin transient radio ejecta in black hole X-ray binaries is not active in Aql X-1. Description: Rising X-ray flux from Aql X-1 was observed on 2009 November 1 (Linares et al. 2009ATel.2288....1L) by the Proportional Counter Array (PCA) on board the RXTE satellite during the ongoing Galactic bulge monitoring program (Markwardt et al. 2000arxt.confE...7M). Here, we present follow-up radio and X-ray data taken during the outburst. On detection of rising X-ray flux, we triggered VLA monitoring at 8.4GHz. we also began observing at 4.8GHz until the source faded below our detection threshold. Further, we reduced all the remaining unpublished archival VLA data, covering the outbursts of 2006 August and 2007 October. We also triggered observations with the Very Long Baseline Array (VLBA) at 8.4GHz. As reported by Tudose et al. (2009ATel.2317....1T), Aql X-1 was observed at 5GHz with the European VLBI Network (EVN) on 2009 November 19 (14:30-19:00UT). Following Altamirano et al. (2008, Cat. J/ApJ/685/436), we used the 16s time-resolution Standard 2 mode PCA data to calculate X-ray colors and intensities. Hard and soft colors were defined as the count rate ratios (9.7-16.0keV/6.0-9.7keV) and (3.5-6.0keV/2.0-3.5keV), respectively, and intensity was defined as the 2.0-16.0keV count rate. Objects: -------------------------------------------- RA (2000) DE Designation(s) -------------------------------------------- 19 11 16.05 +00 35 05.8 Aql X-1 = X Aql X-1 -------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 125 58 X-ray and radio observations of Aql X-1
See also: B/chandra : The Chandra Archive Log (CXC, 1999-2012) B/xmm : XMM-Newton Observation Log (XMM-Newton Science Operation Center, 2012) V/134 : Atlas of Radio/X-ray associations (ARXA) (Flesch, 2010) IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999) J/ApJS/186/378 : Hard X-ray survey from Swift-BAT 2004-2006 (Tueller+, 2010) J/A+A/472/705 : BeppoSAX WFC X-ray source catalogue (SAXWFC) (Verrecchia+, 2007) J/PAZh/32/508 : Hard X-ray Bursts by INTEGRAL in 2003-2004 (Chelovekov+, 2006) J/A+A/411/L59 : INTEGRAL reference catalog (Ebisawa+, 2003) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 10 A10 "YYYY/MM/DD" Date Date of observation 12- 19 F8.2 d MJD-X ? Modified Julian date of RXTE Proportional Counter Array (PCA) observation 21- 26 F6.2 mCrab SX ? PCA flux in milliCrab 28- 31 F4.2 mCrab e_SX ? Uncertainty in PCA 33- 37 F5.3 --- Xh ? Hard color: 9.7-16keV/6-9.7keV count ratio 39- 43 F5.3 --- e_Xh ? Uncertainty in Hard 45- 49 F5.3 --- Xs ? Soft color: 3.5-6keV/2-3.5keV count ratio 51- 55 F5.3 --- e_Xs ? Uncertainty in Soft 57- 64 F8.2 d MJD-a ? Modified Julian date of VLA observation 66 A1 --- l_S8.4a Limit flag on S8.4a 67- 71 F5.2 mJy S8.4a ? VLA 8.4GHz flux density 73- 76 F4.2 mJy e_S8.4a ? Uncertainty in S8.4a 78 A1 --- l_S4.8a Limit flag on S4.8 79- 83 F5.2 mJy S4.8a ? VLA 4.8GHz flux density 85- 88 F4.2 mJy e_S4.8a ? Uncertainty in S4.8 90- 97 F8.2 d MJD-b ? Modified Julian date of Very Long Baseline Array (VLBA) observation 99 A1 --- l_S8.4b Limit flag on S8.4b 100-104 F5.2 mJy S8.4b ? VLBA 8.4GHz flux density 106-109 F4.2 mJy e_S8.4b ? Uncertainty in S8.4b 111-114 F4.2 mJy S5.0 ? European VLBI Network (EVN) 5.0GHz flux density 116-119 F4.2 mJy e_S5.0 ? Uncertainty in S5.0 121 A1 --- f_S5.0 [d] Flag on S5.0 (1) 123-125 A3 --- State [EIS/BS/IS ] X-ray state (2)
Note (1): d = The MJD of the EVN observation was 55154.70. Note (2): EIS, IS and BS denote extreme island state, island state, and banana state, respectively, defined from RXTE observations within 2 days of the radio data.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Jun-2012
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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