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contributious. | contributions. |
To do so would require study of the flow closer to the gravitating mass. specifically across the sonic surface. | To do so would require study of the flow closer to the gravitating mass, specifically across the sonic surface. |
In. principle. a perturbation series in this region could be liuked to the outer one developed here. | In principle, a perturbation series in this region could be linked to the outer one developed here. |
Besides elucidating the momentum trausler through iufall. such a study could also establish AZ analytically as a function of velocity. thus putting accretion theory as a whole on a firmer foundation. | Besides elucidating the momentum transfer through infall, such a study could also establish $\dot M$ analytically as a function of velocity, thus putting accretion theory as a whole on a firmer foundation. |
We eratefully acknowledge useful couversatious from a number of colleagues during the course of the project. | We gratefully acknowledge useful conversations from a number of colleagues during the course of the project. |
These iuclude Jon Arous. Phil Chane. Chris Mcelxee. and Prateek Sharma. | These include Jon Arons, Phil Chang, Chris McKee, and Prateek Sharma. |
We thank the referee Thiery Foglizzo for au iusightful report that helped improve the clarity of our paper. | We thank the referee Thiery Foglizzo for an insightful report that helped improve the clarity of our paper. |
ATL acknowledges support from au NSF Graduate Fellowship. while SWS was partially fuuded by NSF Grant 00082573. | ATL acknowledges support from an NSF Graduate Fellowship, while SWS was partially funded by NSF Grant 0908573. |
is most likely around 2. though the broad emission feature may have a higher ratio on the order of 34. | is most likely around 2, though the broad emission feature may have a higher ratio on the order of 3–4. |
Ser A*. the dynamical center of the Galaxy. vields no HC] detection to an rms level of 0.1 IX ab a resolution of 0.311. | Sgr $^*$, the dynamical center of the Galaxy, yields no HCl detection to an rms level of 0.1 K at a resolution of 0.31. |
.. Similarly. G1.6-0.025. a giant molecular cloud in the Galactic center region5 with no apparent sign5 of star formation. also vields a non-detection. | Similarly, G1.6-0.025, a giant molecular cloud in the Galactic center region with no apparent sign of star formation, also yields a non-detection. |
ser D2(M) and Ser D2CN). on the other haud. show broad strong absorption at both IC! and J=1-Olransilions. | Sgr B2(M) and Sgr B2(N), on the other hand, show broad strong absorption at both HCl and $J=1-0$ transitions. |
From Table 2.. it it clear that the ΠΙΟ] isotopic ratio. based on that of the optical depth. is rather varied. from 4 and over in Mon R2. Ελ10216. and DR21(OIIL). to around 3 in OMC-I. W3(OID. and IRAS16293. down to around 2 in G5.89-0.39. and to nearly reaching parity in W31RS4 and W31IRS5. | From Table \ref{tab:line-fit}, it it clear that the ] isotopic ratio, based on that of the optical depth, is rather varied, from 4 and over in Mon R2, IRC+10216, and DR21(OH), to around 3 in OMC-1, W3(OH), and IRAS16293, down to around 2 in G5.89-0.39, and to nearly reaching parity in W3IRS4 and W3IRS5. |
In comparison. the terrestrial ΠΟ abundance ratio is 23.1. | In comparison, the terrestrial ] abundance ratio is $\sim$ 3.1. |
In addition to the optical depth obtained from hyperfine structure fitting. we can derive other physical parameters from the line profiles bx running LVG simulations to fit the three IICI hvperfine components. | In addition to the optical depth obtained from hyperfine structure fitting, we can derive other physical parameters from the line profiles by running LVG simulations to fit the three HCl hyperfine components. |
RADEX. a computer program developed and maintained bv vanderTaketal.(2007) [or fast non-LTE analvsis of interstellar line spectra. was used in ihe LVG mode to find the best combination of gas densitv ancl ΠΟ column density. that could reproduce the observed line temperatures under eiven gas temperature. | RADEX, a computer program developed and maintained by \citet{vanderTak2007} for fast non-LTE analysis of interstellar line spectra, was used in the LVG mode to find the best combination of gas density and HCl column density that could reproduce the observed line temperatures under given gas temperature. |
The molecular data file for ILC] under RRADEX includes the hyperfine levels of the lowest 8 rotational levels. up to 839 IX above ground level. with rates for radiative and collisional transitions among them. | The molecular data file for HCl under RADEX includes the hyperfine levels of the lowest 8 rotational levels, up to 839 K above ground level, with rates for radiative and collisional transitions among them. |
The collisional rates between ILC] and | The collisional rates between HCl and |
SCRBs with well-determined redshifts. obtained from host galaxy associations (c.e.. Derger2009)). | SGRBs with well-determined redshifts, obtained from host galaxy associations (e.g., \citealt{Berger09}) ). |
Since its launch in late 2001 has detected SCRBs at a rate of ~10 . of which ~1/3 have measured redshifts. | Since its launch in late 2004 has detected SGRBs at a rate of $\sim 10$ $^{-1}$ , of which $\sim 1/3$ have measured redshifts. |
Shown for comparison are the seusitivitv ranges D,zx1.5=295]615] Alpe for detection of NS-NS[NS- mergers«196[L10| byaccordingly... where the factor of z1.5 (included only im this section and 82.1) accounts for the stronger CAV signal from face- mergers. Which characterize the ecometry of GRD jets (o.@.. Iochanek&Piran1993:Schutz 2011)). | Shown for comparison are the sensitivity ranges $D_{\rm r} \approx 1.5\times 196[410] \approx 295[615]$ Mpc for detection of NS-NS[NS-BH] mergers by, where the factor of $\approx 1.5$ (included only in this section and $\S\ref{sec:oa}$ ) accounts for the stronger GW signal from face-on mergers, which characterize the geometry of GRB jets (e.g., \citealt{Kochanek&Piran93,Schutz11}) ). |
Figue 2. illustrates the striking fact that no SCRBs with kuown redshifts have vet occurred within the ALICO/Vireo rauge for NS-NS ierecrs. while oulv two SGRD«s (061201. aud 0809005) have occurred within the NS-BIT rause. | Figure \ref{fig:redshift} illustrates the striking fact that no SGRBs with known redshifts have yet occurred within the ALIGO/Virgo range for NS-NS mergers, while only two SGRBs (061201 and 080905) have occurred within the NS-BH range. |
Though selection effects and low-nunber statistics undoubtedly distort the true redshift distribution from that shown in Figure 2.. at low redshift the distribution should nevertheless scale as Neueoh.x S. | Though selection effects and low-number statistics undoubtedly distort the true redshift distribution from that shown in Figure \ref{fig:redshift}, at low redshift the distribution should nevertheless scale as $\dot{N}_{\rm
GRB,obs}\propto z^{3}$ . |
By füttne the lowest redshift bins to a distribution of this form. we find that <=0.03(0.3) SGRBs per vear are currently being localized bySwift within the ALIGO/Vireo range tor NS-NS(NS-DII)ALICGO/Virso. | By fitting the lowest redshift bins to a distribution of this form, we find that $\lesssim 0.03(0.3)$ SGRBs per year are currently being localized by within the ALIGO/Virgo range for NS-NS(NS-BH). |
. Thus. even assuuiung thatSwift (oy a iuission with simular capabilities) operates simultaneously with ALIGCO/Vireo. SCRBs are clearly not ideal counterparts to localize a large number of merecrs. | Thus, even assuming that (or a mission with similar capabilities) operates simultaneously with ALIGO/Virgo, SGRBs are clearly not ideal counterparts to localize a large number of mergers. |
Obtaining a single CW redshift in this fashiou could require a decade of observations. | Obtaining a single GW redshift in this fashion could require a decade of observations. |
Localization is of course ouly oue desirable virtue of an EM counterpart. | Localization is of course only one desirable virtue of an EM counterpart. |
Due to the short duration of both SCRBs and the CAV signal. aud the short expected delay (= seconds) between them. a time coincidence between hese eveuts is sufficient to euable a statistically coufideut association. | Due to the short duration of both SGRBs and the GW signal, and the short expected delay $\lesssim\,$ seconds) between them, a time coincidence between these events is sufficient to enable a statistically confident association. |
Even if the redshift cannot be obtained. a coincident detection will still confi the astrophysical mature of the CAV signal. prove the connection between SCRBs and NS-NS/NS-DII iiergers. aud allow stuclies of the dependence of the binary inclination on the xoperties of the GRD jet (e.g. lKochauek&Pian 1993)). | Even if the redshift cannot be obtained, a coincident detection will still confirm the astrophysical nature of the GW signal, prove the connection between SGRBs and NS-NS/NS-BH mergers, and allow studies of the dependence of the binary inclination on the properties of the GRB jet (e.g., \citealt{Kochanek&Piran93}) ). |
Coincidence searches for CAV bursts usine the nue and sky coordinates of detected SGBDs were already: conducted during previous LIGO/Vireo Science Buus (e... Abadieetal.20108:Abbott 2010)) To estimate how long ALICO/Vireo must operate before a connection between SGRDs aud. mergers cau be tested. we also plot in Figure 2 an estinate of the low-redshift distribution. but includingeH detectable SCRBs (with or without redslüft information). which we cstimate by uultiplvine the "with redshift” distribution by a factor zz10. | Coincidence searches for GW bursts using the time and sky coordinates of detected SGRBs were already conducted during previous LIGO/Virgo Science Runs (e.g., \citealt{Abadie+10b,Abbott+10}) ) To estimate how long ALIGO/Virgo must operate before a connection between SGRBs and mergers can be tested, we also plot in Figure \ref{fig:redshift} an estimate of the low-redshift distribution, but including detectable SGRBs (with or without redshift information), which we estimate by multiplying the “with redshift” distribution by a factor $\approx 10$. |
This factor accounts for the higher rate. ~20 1. that Canuna-Rav Burst Monitor (6GDM) detects SORBs. as conrpared to the rate with redshift fromSuvft (correcting also for the CDM field of view. which covers ouly ~60 per ceut of the sky). | This factor accounts for the higher rate, $\sim 20$ $^{-1}$ , that Gamma-Ray Burst Monitor (GBM) detects SGRBs, as compared to the rate with redshift from (correcting also for the GBM field of view, which covers only $\sim 60$ per cent of the sky). |
This estimate illustrates that a fewForni bursts over the past few vears probably occured within the ALIGO/Vireo volume. | This estimate illustrates that a few bursts over the past few years probably occurred within the ALIGO/Virgo volume. |
Thus. au albzkv 5- rav inonitor with a seusitivitv simular to FeriCDM could test whether SCRBs originate frou, NS-NS/NS-DII merecrs within just a few vears after ALICO/Vireo reaches full sensitivity. even if it does not lead to a sienificant iniprovenuent in the sky localizations. | Thus, an all-sky $\gamma$ -ray monitor with a sensitivity similar to /GBM could test whether SGRBs originate from NS-NS/NS-BH mergers within just a few years after ALIGO/Virgo reaches full sensitivity, even if it does not lead to a significant improvement in the sky localizations. |
Oue issue raised by the above analysis is that the observed SCRD rate within the ALIGO/Vireo volue. even when corrected for partial «kv coverage. is much lower than the best-bet NS-NS iierger vate of ]ü y.|l N | One issue raised by the above analysis is that the observed SGRB rate within the ALIGO/Virgo volume, even when corrected for partial sky coverage, is much lower than the best-bet NS-NS merger rate of $\sim
40$ $^{-1}$ . |
alkaretal.(2006) estimate that the local volumetric SGRD rate is >10 P? yr.LL which corresponds to au all-sky rate of ΑΠΩaee~0.3 vrD at a distance of =να€200 Mpe (cf. Guetta&Piran2005)). | \citet{Nakar+06} estimate that the local volumetric SGRB rate is $\gtrsim 10$ $^{-3}$ $^{-1}$, which corresponds to an all-sky rate of $\dot{N}_{\rm GRB,all-sky}\sim 0.3$ $^{-1}$ at a distance of $\lesssim D_{\rm r,NS-NS}\approx 200$ Mpc (cf., \citealt{Guetta&Piran05}) ), |
consistent with our cstimates in Figure 2 and still wo orders of maeuitude below ~10 yr!. | consistent with our estimates in Figure \ref{fig:redshift} and still two orders of magnitude below $\sim 40$ $^{-1}$. |
Reconciling lis remaimine discrepancy requires either that the true nerecr rate is lower than the best-bet rate: that all uergers are not accompanicd bv a bright SGRDB: or that he 5-ray emission is beamed οσο, Bosswog&RamirezRuiz2002:Alovetal. 2005)). | Reconciling this remaining discrepancy requires either that the true merger rate is lower than the best-bet rate; that all mergers are not accompanied by a bright SGRB; or that the $\gamma$ -ray emission is beamed (e.g., \citealt{Rosswog&Ramirez-Ruiz02,Aloy+05}) ). |
Expaucing ou this final possibility. if thetypical SGCRD jet las a halbopening angle 0;S7/2. theu ouly a raction fi,zc1cos)m02«| of viewers with observing anglesθε will detect a bright SGRD. | Expanding on this final possibility, if thetypical SGRB jet has a half-opening angle $\theta_j\lesssim \pi/2$, then only a fraction $f_{b,\gamma}\approx 1-\cos\theta_j\approx \theta_{\rm j}^{2}/2\ll 1$ of viewers with observing angles$\theta_{\rm obs}\lesssim \theta_j$ will detect a bright SGRB. |
For all other observers (the0; majority of cases) the prompt Cluission is much dinuner due to relativistic beamine. | For all other observers (the majority of cases) the prompt emission is much dimmer due to relativistic beaming. |
Reconciling the “observed” aud best-bot rate by beaming alone thus requires fr~0.01. or 0;~0.12. similar to the opening angle inferred for GRD0051221À (Burrowsetal.2006:Soderbergct 2006). | Reconciling the “observed” and best-bet rate by beaming alone thus requires $f_{b,\gamma}\sim 0.01$, or $\theta_j\sim 0.12$, similar to the opening angle inferred for 051221A \citep{Burrows+06,Soderberg+06}. |
. A auystery associated with SCBRDsis that ~1/1.1/2 are followed by variable N-ray cuaission with a flueuce colmparable to. or m excess of the initial burst (e.g. Norris&Bonnell2006: Perleyetal. 2009)). | A mystery associated with SGRBs is that $\sim 1/4-1/2$ are followed by variable X-ray emission with a fluence comparable to, or in excess of the initial burst (e.g., \citealt{Norris&Bonnell06}; \citealt{Perley+09}) ). |
Although the origin of this extended euission is still debated. one explanation is that it results from ongoing eunerev output from a highly magnuetized neutron star. which survives the NS-NS inereer (Metzgeretal.2008b: Bueciautinietal. 2011)). | Although the origin of this extended emission is still debated, one explanation is that it results from ongoing energy output from a highly magnetized neutron star, which survives the NS-NS merger \citealt{Metzger+08}; \citealt{Bucciantini+11}) ). |
Regardless of its origin. if some merecrs are indeed accompanied by extended X-ray cussion. this provides an additional poteutial EXD counterpart. especially if the X-ray euidssion is moreisotropic than the SCRB itself (as predicted byseveral models: \lacFadven 20113). | Regardless of its origin, if some mergers are indeed accompanied by extended X-ray emission, this provides an additional potential EM counterpart, especially if the X-ray emission is moreisotropic than the SGRB itself (as predicted byseveral models: \citealt{MacFadyen+05,Metzger+08,Barkov&Pozanenko11,Bucciantini+11}) ). |
Considering alternative prompt counterparts is ecrimanebecause the lifetime of ift and ave uncertain. while the next generation of proposed hieh-energy trausieut satellites (6.9.. Janus. Lobster) are most sensitive at soft N-rav (rather than rav) energies. which could reduce their seusitivitv to detecting the prompt SCRD phase. | Considering alternative prompt counterparts is germanebecause the lifetime of and are uncertain, while the next generation of proposed high-energy transient satellites (e.g., Janus, Lobster) are most sensitive at soft X-ray (rather than $\gamma-$ ray) energies, which could reduce their sensitivity to detecting the prompt SGRB phase. |
The difficulty | The difficulty |
The brightest X-ray source coincides in both observations with the unresolved binary star. | The brightest X-ray source coincides in both observations with the unresolved binary star. |
Two new X-ray sources. not seen in the 2003 data. are detected in the 2008 image. | Two new X-ray sources, not seen in the 2003 data, are detected in the 2008 image. |
Especially remarkable is the faint source in the SW elongation of ZCCMa (named 'J henceforth). | Especially remarkable is the faint source in the SW elongation of CMa (named `J' henceforth). |
The position angle of this source is (225+5y. roughly in agreement with the orientation of the blue-shifted part of the optical jet detected by ?.. | The position angle of this source is $(225 \pm 5)^\circ$, roughly in agreement with the orientation of the blue-shifted part of the optical jet detected by \cite{Poetzel89.1}. |
In the broad band image (0.2.— SkkeV) this source is separated by 2.1" from CCMa. | In the broad band image $0.2-8$ keV) this source is separated by $2.4^{\prime\prime}$ from CMa. |
If only photons below 1kkeV are considered the 2008 image shows elongated emission along the same axis suggesting a chain of weak X-ray sources extending to the SW of ZCCMa. | If only photons below $1$ keV are considered the 2008 image shows elongated emission along the same axis suggesting a chain of weak X-ray sources extending to the SW of CMa. |
There is no significant soft excess in the SW direction during 2003 (see zoom in Fig. 2). | There is no significant soft excess in the SW direction during 2003 (see zoom in Fig. \ref{fig:acis_images}) ). |
The remaining X-ray sources (labels “N95-B* and N95-C" in Fig. 2)) | The remaining X-ray sources (labels `N95-B' and `N95-C' in Fig. \ref{fig:acis_images}) ) |
are tentatively identified with pre-MS candidates mentioned by ?.. | are tentatively identified with pre-MS candidates mentioned by \cite{Nakajima95.1}. |
In the following we concentrate on the analysis of the X-ray emission associated with CCMa and its jet. | In the following we concentrate on the analysis of the X-ray emission associated with CMa and its jet. |
We calculated the source count rates in the following way: First. the point-spread-function (PSF) was computed for each X-ray position. | We calculated the source count rates in the following way: First, the point-spread-function (PSF) was computed for each X-ray position. |
A circular source photon extraction region was defined as the area that contains 95 to 90 The background was extracted individually from a squared region centered on the source extraction. area and several times larger than the latter one. | A circular source photon extraction region was defined as the area that contains $95$ to $90$ The background was extracted individually from a squared region centered on the source extraction area and several times larger than the latter one. |
Circular areas centered on the positions of the X-ray sources were excluded from the background area. | Circular areas centered on the positions of the X-ray sources were excluded from the background area. |
The S/N was computed from the counts summed in the source and background areas. respectively. after applying the appropriate area scaling factor to the background counts. | The S/N was computed from the counts summed in the source and background areas, respectively, after applying the appropriate area scaling factor to the background counts. |
In practice. the background is very low (a fraction of a count in the source extraction area). | In practice, the background is very low (a fraction of a count in the source extraction area). |
Finally. count rates were obtained using the exposure time at the source position extracted from the exposure map. | Finally, count rates were obtained using the exposure time at the source position extracted from the exposure map. |
We have estimated a 05 at the position of F in the Dec 2003 observation (marked red in Fig. | We have estimated a $95$ at the position of `J' in the Dec 2003 observation (marked red in Fig. |
2 left) using the algorithm of ?.. | \ref{fig:acis_images} left) using the algorithm of \cite{Kraft91.1}. |
In Table 2 we summarize the relevant X-ray parameters of the ZCCMa binary and the source J identified with the jet. | In Table \ref{tab:xrayparams} we summarize the relevant X-ray parameters of the CMa binary and the source `J' identified with the jet. |
An individual response matrix and auxiliary response were extracted for the position of each source using standard CLAO tools. | An individual response matrix and auxiliary response were extracted for the position of each source using standard CIAO tools. |
The spectrum of the brighter source (ZCCMa) was binned to à minimum of 10 counts per bin and that of the fainter one CJ) to 5 counts per bin. | The spectrum of the brighter source CMa) was binned to a minimum of $10$ counts per bin and that of the fainter one (`J') to $5$ counts per bin. |
As mentioned above. the background of ACIS is negligibly low. | As mentioned above, the background of ACIS is negligibly low. |
We fitted the spectra in the 12.4.0 environment with à one- or temperature thermal model subject to photo-absorption andAPEC]. respectively). | We fitted the spectra in the 12.4.0 environment with a one- or two-temperature thermal model subject to photo-absorption and, respectively). |
For the brighter source CCMa) the 1-T fit of the Dec 2008 observation displays substantial residuals slightly below ] kkeV. and we resort to the 2-T model. | For the brighter source CMa) the $1$ -T fit of the Dec 2008 observation displays substantial residuals slightly below $1$ keV, and we resort to the $2$ -T model. |
The best fit Ny is τὴ:∙ 7. compatible with the range of values published for the optical extinetion “ly=2.1...L.6mmag (22).. | The best fit $N_{\rm H}$ is $7^{+5}_{-6} \cdot 10^{21}\,{\rm cm^{-2}}$ , compatible with the range of values published for the optical extinction $A_{\rm V}=2.4 ... 4.6$ mag \citep{Elia04.1, Acke04.1}. |
Assuming a particle density of Όλο° the galactic absorption. at lkkpe amounts to ~107!«n7. | Assuming a particle density of $0.3\,{\rm cm^{-3}}$ the galactic absorption at $1$ kpc amounts to $\sim 10^{21}\,{\rm cm^{-2}}$. |
Therefore. ZCCMa may have some additional absorption related to the star forming environment. | Therefore, CMa may have some additional absorption related to the star forming environment. |
On the other hand. our measurement does not rule out negligible circumstellar absorption. | On the other hand, our measurement does not rule out negligible circumstellar absorption. |
In our best-fit model the soft component (47;0.LS kkeV) dominates over the hard component (Ada—7.5 KkeV: unconstrained) with. an emission2. measure logEAL,fom2--.mο VS. losoEALJem?|=53.11!"0.1.ae. | In our best-fit model the soft component $kT_1=0.4^{+0.7}_{-0.2}$ keV) dominates over the hard component $kT_2 \sim 7.5$ keV; unconstrained) with an emission measure $\log{EM_1}\,{\rm [cm^{-3}]}=53.9^{+1.2}_{-0.6}$ vs. $\log{EM_2}\,{\rm [cm^{-3}]}=53.1^{+0.4}_{-0.3}$. |
Due to the large confidence intervals. of the spectral parameters. we determine only a lower limit on the X-ray flux. adopting a minimum Vj of —22q0?emi27? coming. up for: the interstellar. absorptior. but eglecting any possible contribution from the environment of the star. | Due to the large confidence intervals of the spectral parameters, we determine only a lower limit on the X-ray flux, adopting a minimum $N_{\rm H}$ of $\sim 10^{21}\,{\rm cm^{-2}}$ coming up for the interstellar absorption but neglecting any possible contribution from the environment of the star. |
We find f.>16-10tere/cu?/s for the 0.5 S.OKkeV band. corresponding to logLy|evg/s]730.3 at a "Sistance of 1050 ppc. | We find $f_{\rm x} > 1.6 \cdot 10^{-14}\,{\rm erg/cm^2/s}$ for the $0.5-8.0$ keV band, corresponding to $\log{L_{\rm x}}\,{\rm [erg/s]}> 30.3$ at a distance of $1050$ pc. |
For the Dec 2003 observation due to low photon statistics we can not formally exclude the 1-T model. | For the Dec 2003 observation due to low photon statistics we can not formally exclude the $1$ -T model. |
Iso-thermal models are known to be an oversimplification and the number of thermal components needed to fit stellar X-ray spectra generally increases with photon statistics. | Iso-thermal models are known to be an oversimplification and the number of thermal components needed to fit stellar X-ray spectra generally increases with photon statistics. |
We do not present à detailed spectral analysis of this data set because the quality is poor. | We do not present a detailed spectral analysis of this data set because the quality is poor. |
However. we can test the compatibility of the 2003 spectrum with the 2-T model parameters derived from the 2008 observation. | However, we can test the compatibility of the 2003 spectrum with the 2-T model parameters derived from the 2008 observation. |
Indeed. we find from a direct comparison of the 2008 best-fit model to the spectrum observed in 2003. without fitting it to the data. a V2.=1.0 (5 d.o.f.). | Indeed, we find from a direct comparison of the 2008 best-fit model to the spectrum observed in 2003, without fitting it to the data, a $\chi^2_{\rm red} = 1.0$ $5$ d.o.f.). |
The good agreement is also evident from Fig. | The good agreement is also evident from Fig. |
3 where we plot both observed spectra together with the best-fit model (dashed lines) of the 2008 data. | \ref{fig:acis_spectra} where we plot both observed spectra together with the best-fit model (dashed lines) of the 2008 data. |
Differences in the appearance of the two spectra in Fig. | Differences in the appearance of the two spectra in Fig. |
3 are due to the fact that the data and the model are shown folded with the instrument response matrix. | \ref{fig:acis_spectra} are due to the fact that the data and the model are shown folded with the instrument response matrix. |
We recall here that CCMa ts located on two different CCD chips and at different off-axis angle in the 2003 and 2008 data sets (see Table 1)). and this implies different spectral response and effective area. | We recall here that CMa is located on two different CCD chips and at different off-axis angle in the 2003 and 2008 data sets (see Table \ref{tab:obslog}) ), and this implies different spectral response and effective area. |
The fainter source CJ) has only 20 counts in Dec 2008. | The fainter source (`J') has only $20$ counts in Dec 2008. |
The 1-T model gives the same absorption as found for CCMa albeit with even larger uncertainties (Vy,=7:οcm 2). | The $1$ -T model gives the same absorption as found for CMa albeit with even larger uncertainties $N_{\rm H} = 7^{+8}_{-7} \cdot 10^{21}\,{\rm cm^{-2}}$ ). |
The large error bar of the column density makes 1t impossible to determine the emission measure and flux of this source to even an order of magnitude precision. | The large error bar of the column density makes it impossible to determine the emission measure and flux of this source to even an order of magnitude precision. |
The temperature of source "J is also not well constrained (0.21 kkeV) but probably relatively soft. | The temperature of source `J' is also not well constrained $0.2^{+0.8}_{-0.1}$ keV) but probably relatively soft. |
We find à median photon energy of 0.9 kkeV. for F. versus 1.2kkeV for ZCCMa. | We find a median photon energy of $0.9$ keV for `J' versus $1.2$ keV for CMa. |
Analogously to the case of ZCCMa. we estimate a lower limit for the X- flux of P adopting Ny of ~107!ci? corresponding to the expected interstellar absorption. | Analogously to the case of CMa, we estimate a lower limit for the X-ray flux of `J' adopting $N_{\rm H}$ of $\sim 10^{21}\,{\rm cm^{-2}}$ corresponding to the expected interstellar absorption. |
The derived. value of E2.10.5Porefem?2/s translates to logLyleves]>29. Lif we | The derived value of $2 \cdot 10^{-15}\,{\rm erg/cm^2/s}$ translates to $\log{L_{\rm x}}\,{\rm [erg/s]}> 29.4$ if we |
'The algorithm, which we describe below in detail, allows us also to measure the degree of intrinsic variation in the apparent surface area for each source that is consistent with the width of the flux-temperature correlation. | The algorithm, which we describe below in detail, allows us also to measure the degree of intrinsic variation in the apparent surface area for each source that is consistent with the width of the flux-temperature correlation. |
Even though we compare spectra in relatively narrow flux bins, the different observing modes as well as the different number of PCUs used in each observation result in a wide range of count rates and, hence, in a wide range of formal errors. | Even though we compare spectra in relatively narrow flux bins, the different observing modes as well as the different number of PCUs used in each observation result in a wide range of count rates and, hence, in a wide range of formal errors. |
This necessitates the use of the Bayesian approach we describe below as opposed to, e.g., performing x? fits of the distributions over blackbody normalization. | This necessitates the use of the Bayesian approach we describe below as opposed to, e.g., performing $\chi^2$ fits of the distributions over blackbody normalization. |
Observations in star forming regions have revealed that the ootostellar collapse of a molecular cloud. core is. usually accompanied by outllow phenomena (e.ο.77)... which were already. discovered back in the 1970s (272)... | Observations in star forming regions have revealed that the protostellar collapse of a molecular cloud core is usually accompanied by outflow phenomena \citep[e. g.][]{Wu2004uq,Bally2007fk}, which were already discovered back in the 1970s \citep{Zuckerman1975fj,Kwan1976yq,Zuckerman1976kx}. |
Usually. ootostellar outllows ave classified into two tvpes. optical jets or molecular outfows. | Usually, protostellar outflows are classified into two types, optical jets or molecular outflows. |
The latter typically exhibit slow velocities ancl wide opening angles. and are observationally identified by line emission from their CO molecules. | The latter typically exhibit slow velocities and wide opening angles, and are observationally identified by line emission from their CO molecules. |
The ormer. having narrow opening angles and high velocities. are observed optically. | The former, having narrow opening angles and high velocities, are observed optically. |
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