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other possible solutions to (this issue (e.g. cold spots on the DD surface) see (2011). | other possible solutions to this issue (e.g. cold spots on the BD surface) see \citet{bouchy11}. |
For a low sdB mass of ~0.25M. the companions mass-raclius relation is also consistent with theory. | For a low sdB mass of $\simeq0.25\,M_{\rm \odot}$ the companion's mass-radius relation is also consistent with theory. |
In this case the companion mass would be 0.045AZ... | In this case the companion mass would be $0.045\,M_{\rm \odot}$. |
A third possibility mav be that the progenitor of the πα was originally more massive. | A third possibility may be that the progenitor of the sdB was originally more massive. |
In this case the sdD mass could be as low as ~0.2M... ancl Che svstem as well as the substellar companion would be much vounger. | In this case the sdB mass could be as low as $\simeq0.3\,M_{\rm \odot}$ and the system as well as the substellar companion would be much younger. |
Since voung BDs are considerably larger. this may. also lead to a consistent solution (see Fig. 4)). | Since young BDs are considerably larger, this may also lead to a consistent solution (see Fig. \ref{mr-relation}) ). |
In the cases discussed above. the mass of the companion ranges between 0.045.romsM. and 0.068.trsM... | In the cases discussed above, the mass of the companion ranges between $0.045_{-0.002}^{+0.003}\,M_{\rm \odot}$ and $0.068_{-0.003}^{+0.003}\,M_{\rm \odot}$. |
The most conservative theoretical lower limit for core hvdrogen-burning (~(LOTM... is right at the border of this range. | The most conservative theoretical lower limit for core hydrogen-burning \citep[$\simeq0.07\,M_{\rm \odot}$ is right at the border of this range. |
We therefore conclude that Che companion is most likely a brown dwarf. | We therefore conclude that the companion is most likely a brown dwarf. |
Iowever. given that the sdD mass is not strictly constrained. the companion may also be a star of extremely low mass. | However, given that the sdB mass is not strictly constrained, the companion may also be a star of extremely low mass. |
We have presented a spectroscopic and photometric analysis of the IW Vir type eclipsing sdD star JOS205+0008. discovered in the course of the MUCIIFUSS project. | We have presented a spectroscopic and photometric analysis of the HW Vir type eclipsing sdB star J08205+0008, discovered in the course of the MUCHFUSS project. |
Although the mass of the sdD is not vet tightly constrained. it is important to stress that (he companion remains below the core hvdrogen-burning limit lor reasonable subclwarl masses ranging [rom 0.25M. to 0.47M.. | Although the mass of the sdB is not yet tightly constrained, it is important to stress that the companion remains below the core hydrogen-burning limit for reasonable subdwarf masses ranging from $0.25\,M_{\rm \odot}$ to $0.47\,M_{\rm \odot}$. |
The inclination constraint [rom eclipses means that J082054-0008 has the lowest unambigeuouslv measured companion mass vet found in a subdwarl B binary. | The inclination constraint from eclipses means that J08205+0008 has the lowest unambiguously measured companion mass yet found in a subdwarf B binary. |
The question whether (he sdB is burning helium in its core or not remains open lor now. | The question whether the sdB is burning helium in its core or not remains open for now. |
Time resolved high resolution spectroscopy is necessary (o measure both (he 0,4sin and the logg of the subclwarl with high accuracy. | Time resolved high resolution spectroscopy is necessary to measure both the $v_{\rm rot}\sin{i}$ and the $\log{g}$ of the subdwarf with high accuracy. |
Combined with a high-quality multi-colour light curve much tighter constraints could be put on this unique binary svstem. | Combined with a high-quality multi-colour light curve much tighter constraints could be put on this unique binary system. |
The [act that (he sdB is situated on the ENB is a strong argument in favour of the EILD-scenario. because post-RGB objects are very rare and not related to the ENB. | The fact that the sdB is situated on the EHB is a strong argument in favour of the EHB-scenario, because post-RGB objects are very rare and not related to the EHB. |
As witnessed by the IWVir type svstems. stellar companions with masses as low as O.1.U. are able (to eject a common envelope and form an sdB star without being destrovec. | As witnessed by the Vir type systems, stellar companions with masses as low as $0.1\,M_{\rm \odot}$ are able to eject a common envelope and form an sdB star without being destroyed. |
The case of J082054-0008 demonstrates that even lower mass objects. i.e. substellar objects. are sullicient. | The case of J08205+0008 demonstrates that even lower mass objects, i.e. substellar objects, are sufficient. |
This finding can be used to constrain theoretical models | This finding can be used to constrain theoretical models |
region where all the four transitions are spatially co-incicent. | region where all the four transitions are spatially co-incident. |
In any case. thermal emission or absorption from OLL will generally not be detected with VLBI. | In any case, thermal emission or absorption from OH will generally not be detected with VLBI. |
‘Table 2 lists the two candidate regions that are situated very close to cach other and hence simultaneously observable with the 107 ΟΛΗ beam. | Table \ref{sourcetable} lists the two candidate regions that are situated very close to each other and hence simultaneously observable with the $10\degr$ GMRT beam. |
For the observations. we used four antennas of the GARE on which the low frequency feeds designed and developed by the Raman Research Institute. Bangalore. India(UclavaShankaretal.2009) have been installed. | For the observations, we used four antennas of the GMRT on which the low frequency feeds designed and developed by the Raman Research Institute, Bangalore, \citep{amiri} have been installed. |
These feeds have frequency coverage from 30 MlIIz to 90 MlIz. | These feeds have frequency coverage from 30 MHz to 90 MHz. |
Phe GMICE receiver chain was used till the baseband. unit to filter the required section of the band from 50 MlIz to 58 MllIZ centered at 54 Mllz. | The GMRT receiver chain was used till the baseband unit to filter the required section of the band from 50 MHz to 58 MHz centered at 54 MHz. |
Only one sideband of the receiver was used - consequentIv the selected: band. was placed in the upper sideband(U with 54 MlITz falling at the centre of the sideband. | Only one sideband of the receiver was used - consequently the selected band was placed in the upper sideband(USB) with 54 MHz falling at the centre of the sideband. |
The reasonS13) for doing so will be explained below. | The reason for doing so will be explained below. |
We used the CMBRE Software SD)(Itoval.2009) [or recording the raw voltage data. | We used the GMRT Software \citep{gsb} for recording the raw voltage data. |
The GSB is a cluster of high-performance PCs connected. by ethernet ancl communicating through the ALPE protocol. | The GSB is a cluster of high-performance PCs connected by ethernet and communicating through the MPI protocol. |
Lt operates in several modes such as raw voltage recorder. realtime interferometric correlator. pulsar receiver. ollline interferometer and beamformer. with facility to do inbuilt xuidpass filtering in the first three modes. | It operates in several modes such as raw voltage recorder, realtime interferometric correlator, pulsar receiver, offline interferometer and beamformer, with facility to do inbuilt bandpass filtering in the first three modes. |
We exploited the jigh bandwidth sampler to record 8.333. MlIE2 of the band at the Nvquist rate. | We exploited the high bandwidth sampler to record 8.333 MHz of the band at the Nyquist rate. |
At the time the observation was carried out. the GSB was operational for. dual-sideband: and. one »xolarization. | At the time the observation was carried out, the GSB was operational for dual-sideband and one polarization. |
However. by re-wiring the inputs to the GSB. we obtained both polarizations but one sideband. | However, by re-wiring the inputs to the GSB, we obtained both polarizations but one sideband. |
This was he reason for putting the band of interest - 50 MllIz to 58 Mllz - in the upper sideband of the baseband. receiver. | This was the reason for putting the band of interest - 50 MHz to 58 MHz - in the upper sideband of the baseband receiver. |
To reduce data volume. a decimating subroutine was added o the recording program to desample the voltage data to νοδι rate. | To reduce data volume, a decimating subroutine was added to the recording program to desample the voltage data to Nyquist rate. |
Lt is to be noted that though the baseband ilter spans 50-58 MlIz. the GSB samples 50-58.333. MIIZ rvecause the sampling frequency of the GSB is 33.33 MIL. | It is to be noted that though the baseband filter spans 50-58 MHz, the GSB samples 50-58.333 MHz because the sampling frequency of the GSB is 33.33 MHz. |
The observations were carried out on 12 March. 2009. recording the data for about five hours. | The observations were carried out on 12 March 2009, recording the data for about five hours. |
Before. recording he data on the target. a lew minutes of test. data was acquired: with default. gains and its RAIS was calculated. | Before recording the data on the target, a few minutes of test data was acquired with default gains and its RMS was calculated. |
The gains of the samplers were then adjusted so that the ‘all range of the S-bit sampler accommodated 6o. where e is the RATS. | The gains of the samplers were then adjusted so that the full range of the 8-bit sampler accommodated $6\sigma$, where $\sigma$ is the RMS. |
A few such iterations were performed until the eains converged. | A few such iterations were performed until the gains converged. |
The final gain table was Loaded into the samplers ancl data recording was commenced. | The final gain table was loaded into the samplers and data recording was commenced. |
Though the sampler clocks with a period of 33 ns. i.e. 33 Msps. every other sample was discarded to achieve Nyquist rate and keep the data volume within limits. | Though the sampler clocks with a period of 33 ns, i.e. 33 Msps, every other sample was discarded to achieve Nyquist rate and keep the data volume within limits. |
At the end of five hours of observation. we had about 270 GB of data per antenna per polarization. there being a total of four antennas with two polarizations cach. | At the end of five hours of observation, we had about 270 GB of data per antenna per polarization, there being a total of four antennas with two polarizations each. |
Data were recorded as a contiguous time-series with a sampling period of 66 ns(post-clecimation) | Data were recorded as a contiguous time-series with a sampling period of 66 ns(post-decimation). |
Each polarisation from cach of the four antennas was recorded separately on individual disks. | Each polarisation from each of the four antennas was recorded separately on individual disks. |
The format of the recorded data necessitated writing of special software to process them. | The format of the recorded data necessitated writing of special software to process them. |
The aim was to detect. if any. very narrow spectral lines. | The aim was to detect, if any, very narrow spectral lines. |
Since the observing frequency. is centered around. 54 Mllz. high velocity. resolution is possible onky with very high spectral resolution. | Since the observing frequency is centered around 54 MHz, high velocity resolution is possible only with very high spectral resolution. |
Llowever. since we were looking for spectral features within a limited range of LSIt velocities. data were bandpass filtered around the region ofinterest and desaimpled. | However, since we were looking for spectral features within a limited range of LSR velocities, data were bandpass filtered around the region of interest and desampled. |
We used the Intel LPP routines in our program to construct bandpass filters of specified: pass and stop bands. | We used the Intel IPP routines in our program to construct bandpass filters of specified pass and stop bands. |
The filter was designed such that an integer number of non-overlapping filters. M. of a specified. bandwidth completely filled the observed. bandwidth of 8.333 MIIz. | The filter was designed such that an integer number of non-overlapping filters, M, of a specified bandwidth completely filled the observed bandwidth of 8.333 MHz. |
The filtered data is then decimated by the same factor M. “Phis operation is called bandpass sampling. | The filtered data is then decimated by the same factor M. This operation is called bandpass sampling. |
We chose AL=90 for the 55 Alllz OL line ancl 2048 channelswithin the passband to allow a velocity resolution of 0.25 fins1 ver channel. | We chose M=90 for the 55 MHz OH line and 2048 channelswithin the passband to allow a velocity resolution of 0.25 $km~s^{-1}$ per channel. |
For the 53 Alllz ΟΙ line. Al=so0 with 2048 channels. the velocity resolution obtained was 028 Ais| per channel. | For the 53 MHz OH line, M=80 with 2048 channels, the velocity resolution obtained was 0.28 $km~s^{-1}$ per channel. |
Al was chosen differently to accommodate the expected line requencies in both cases within the central of the band. | M was chosen differently to accommodate the expected line frequencies in both cases within the central of the band. |
After filtering and desampling. approximately every )25 second of cata was Fourier transformed. with the Intel IPP EFT routine and then squared. | After filtering and desampling, approximately every 0.25 second of data was Fourier transformed with the Intel IPP FFT routine and then squared. |
The power spectrum or cach block of the time series and. hence the cumulative power spectrum. for cach polarization was obtained. | The power spectrum for each block of the time series and hence the cumulative power spectrum for each polarization was obtained. |
The calculated. Doppler shift. of the expected line. during. the observation was less than the width of one channel. | The calculated Doppler shift of the expected line during the observation was less than the width of one channel. |
The power spectra were visually inspected for REL. | The power spectra were visually inspected for RFI. |
Phe 55 MlIz yasshbancl was found to be relatively clean ane unallected w REL exeept by a very weak. spectrally narrow. feature at around 30 fins+ LSR velocity that manifests only in the cumulative power spectrum. | The 55 MHz passband was found to be relatively clean and unaffected by RFI except by a very weak, spectrally narrow, feature at around 30 $km~s^{-1}$ LSR velocity that manifests only in the cumulative power spectrum. |
Since this was away from the region of interest. ic. 40-70 Aims we chose to ignore it. | Since this was away from the region of interest, i.e. 40-70 $km~s^{-1}$, we chose to ignore it. |
The cumulative spectra from all the polarizations save one. which had a bad bancdpass. were added. | The cumulative spectra from all the polarizations save one, which had a bad bandpass, were added. |
Thus. ellectively the four antennas were used like four single-clish spectrometers in the incoherent mode. | Thus, effectively the four antennas were used like four single-dish spectrometers in the incoherent mode. |
The 53. MlIz: passband. on the contrary. was found to be severely allected by REL to such an extent that it had to be abandoned altogether. | The 53 MHz passband, on the contrary, was found to be severely affected by RFI to such an extent that it had to be abandoned altogether. |
Figure 3. shows the final cumulative averaged. spectrum obtained from seven out of the eight available polarizations of the four antennas. | Figure \ref{psfit} shows the final cumulative averaged spectrum obtained from seven out of the eight available polarizations of the four antennas. |
The velocity resolution is 0.25Ams channel | The velocity resolution is $0.25\ km~s^{-1}$ per channel. |
The ordinate is the baseline-subtracted. line-o-continuum flux ratio. after fitting for the baseline with a second order polynomial for the passband shown in the plot. | The ordinate is the baseline-subtracted line-to-continuum flux ratio, after fitting for the baseline with a second order polynomial for the passband shown in the plot. |
At around the expected LSR velocity of 46 Fms.|. where he 1720 Mllz line is seen inverted towards W44 in as many as 25 hotspots(Claussenetal.1997).. there is a weak 4c spectral emission feature. whose peak is 0.006 in units of ine-to-continum temperature ratio. CEr-T,)/T.. | At around the expected LSR velocity of 46 $km~s^{-1}$, where the 1720 MHz line is seen inverted towards W44 in as many as 25 \citep{claussen}, there is a weak $\sim$ $\sigma$ spectral emission feature, whose peak is 0.006 in units of line-to-continuum temperature ratio, $_l$ $_c$$_c$. |
Phe RAIS optical depth is 0.0014 units over a 0.25 fins* channel. | The RMS optical depth is 0.0014 units over a 0.25 $km~s^{-1}$ channel. |
We conclude the 55 MIIz ΟΙ line is not detected to the ta imit. | We conclude the 55 MHz OH line is not detected to the $\sigma$ limit. |
However. this feature becomes more. prominent(see ligure 4)) when the spectrum is smoothed to 1&m5" commensurate with the velocity widths of the hotspots listed w Claussenetal. (1997). | However, this feature becomes more prominent(see Figure \ref{psfit_smoothed}) ) when the spectrum is smoothed to $1\ km~s^{-1}$ , commensurate with the velocity widths of the hotspots listed by \citet{claussen}. . |
. We assume that. the svstem emperature is dominated by the sky temperature at these | We assume that the system temperature is dominated by the sky temperature at these |
(category 4) are shown as filled circles. | (category 4) are shown as filled circles. |
In order to determine (the phase of the X-ray main pulse we have excluded all data points that were deemed flawecl (i... in (he first three categories above). | In order to determine the phase of the X-ray main pulse we have excluded all data points that were deemed flawed (i.e., in the first three categories above). |
Least-squares [its (weighted averages) to the results from the three dillerent peak-finding algorithms that we used lead us to conclude that the X-ray main pulse leads (he radio main pulse (as defined by the radio timing ephemerides) by 10.2540.15 milliperiod. or 34445 is. with a reduced 4? of 1.3. | Least-squares fits (weighted averages) to the results from the three different peak-finding algorithms that we used lead us to conclude that the X-ray main pulse leads the radio main pulse (as defined by the radio timing ephemerides) by $\pm$ 0.15 milliperiod, or $\pm$ 5 $\mu$ s, with a reduced $\chi^{2}$ of 1.3. |
The quoted errors represent the differences between the results from the three methods. | The quoted errors represent the differences between the results from the three methods. |
The statistical errors in (he three individual fits are smaller. | The statistical errors in the three individual fits are smaller. |
In addition. of course. there is still the uncertainty of the 40 yas svstematic error in (he radio ephemerides. | In addition, of course, there is still the uncertainty of the 40 $\mu$ s systematic error in the radio ephemerides. |
We emphasize that. although we believe these error estimates (o be realistic. a dillerent definition of the pulse phase may lead (ο larger discrepancies. | We emphasize that, although we believe these error estimates to be realistic, a different definition of the pulse phase may lead to larger discrepancies. |
Ideally. one should analvze the data that are available in the different spectral bands with a uniform pulse definition. | Ideally, one should analyze the data that are available in the different spectral bands with a uniform pulse definition. |
The result obtained by Kuiperetal.(2003) of. 2804-40. pis for a single INTEGRAL observation is probably to be considered consistent will our [indines. especially since it used a liming ephemeris record αἱ MJD 52685 (hat gives rise to slightly elevated phase values in our data. | The result obtained by \citet{kuip2003} of $\pm$ 40 $\mu$ s for a single INTEGRAL observation is probably to be considered consistent with our findings, especially since it used a timing ephemeris record at MJD 52685 that gives rise to slightly elevated phase values in our data. |
However. the phases that thev quote for the main pulse on MJD 52682 ancl MJD 52697. derived [rom the same RATE observations that we have used. differ from our values bv 41.7 and 41.1 mülliperiods. respectively. | However, the phases that they quote for the main pulse on MJD 52683 and MJD 52697, derived from the same RXTE observations that we have used, differ from our values by +1.7 and +1.1 milliperiods, respectively. |
We believe that. this difference is due to the definition of the phase that is used by these authors. | We believe that this difference is due to the definition of the phase that is used by these authors. |
Ixuiperetal.(2003). define the phase of the main peak as (he position of an asvimnietric Lorentzian fit to the phase range 0.95 {ο 1.05. | \citet{kuip2003} define the phase of the main peak as the position of an asymmetric Lorentzian fit to the phase range 0.95 to 1.05. |
This definition. in our opinion. is not as free of model-cepencent assumptions as our analvsis methodology: it appears that there is à svstematic offset of about 40-50 pts. Note (hat. since these authors used the same Jodrell Bank timing ephemeris records. the radio svslenmatic error does not play a role here. | This definition, in our opinion, is not as free of model-dependent assumptions as our analysis methodology; it appears that there is a systematic offset of about 40-50 $\mu$ s. Note that, since these authors used the same Jodrell Bank timing ephemeris records, the radio systematic error does not play a role here. |
As to the question whether the lag between the X-ray ancl radio pulses is constant in phase (i.e. the lag is rotational in nature) or in time (ie. the lag represents a pathlength difference). the data are not conclusive. | As to the question whether the lag between the X-ray and radio pulses is constant in phase (i.e., the lag is rotational in nature) or in time (i.e., the lag represents a pathlength difference), the data are not conclusive. |
The former would require the phase offset in Fie. | The former would require the phase offset in Fig. |
to be constant with time. while (he latter would require the phase to increase nearly with a slope of +1.0x10* period/day. | \ref{fig2} to be constant with time, while the latter would require the phase to increase linearly with a slope of $+1.0\times10^{-8}$ period/day. |
A linear fit to the good data in Fig. | A linear fit to the good data in Fig. |
2. vields a slope of (43.3+2.0)x10". | \ref{fig2} yields a slope of $(+3.3\pm2.0)\times10^{-7}$. |
This result is probably affected. by Malmenist bias and. possibly other sources of svstematic errors. | This result is probably affected by Malmquist bias and possibly other sources of systematic errors. |
Unless our measurement accuracy can be dramatically improved. it will require at least another seven vears of monitoring before we can answer this «question defimitivelv in this manner. | Unless our measurement accuracy can be dramatically improved, it will require at least another seven years of monitoring before we can answer this question definitively in this manner. |
If indeed we are dealing with a time olfset. this would correspond to a pathlength difference of about 100 km. | If indeed we are dealing with a time offset, this would correspond to a pathlength difference of about 100 km. |
Additional analvsis of the RATE data reveals that the PCA and HIENXTE pulses are perfectly aligned (o within 1 milliperiod (1... no phase change over the 2 (to 30 keV energy | Additional analysis of the RXTE data reveals that the PCA and HEXTE pulses are perfectly aligned to within 1 milliperiod (i.e., no phase change over the 2 to 30 keV energy |
Braudenbure ct al. (1990)) | Brandenburg et al. \cite{brandenburg90}) ) |
extended ai 3D lydvodvuaimical code to the case of maguetoconvection. including the effect of rotation. | extended a 3D hydrodynamical code to the case of magnetoconvection, including the effect of rotation. |
Subsequently. ai spontancous dynamo instability was observed in the siauulatious (Nordlund et al. 1992.. | Subsequently, a spontaneous dynamo instability was observed in the simulations (Nordlund et al. \cite{nordlund92}, |
Drandenburg et al. 1996)). | Brandenburg et al. \cite{brandenburg96}) ). |
Recent simmlations of isotropically forced helical turbulence (Brandenburg 2001)) have verified the existence of large scale dynamo action. and it was possible to identify this as the result of an à effect Gu the sense of anon-local inverse cascade). | Recent simulations of isotropically forced helical turbulence (Brandenburg \cite{brandenburg00}) ) have verified the existence of large scale dynamo action, and it was possible to identify this as the result of an $\alpha$ effect (in the sense of a inverse cascade). |
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