PoS(MQW7)004 http://pos.sissa.it/ ce. lem with the relativistic reflection s key to learning about the disk/jet eady and powerful jets is when they pectra, and it seems that either there nd possible problems with our under- d even our basic picture of this state is have led to questions about whether we rnia, Berkeley, CA 94720-7450, st challenge to the standard truncated disk ive Commons Attribution-NonCommercial-ShareAlike Licen

[email protected] For microquasars, the one time when these systems exhibit st models used to explain the broad iron features. are in the hard state.connection. Thus, Recent observational our and understanding theoretical of results this state i is a problem with the truncated disk picture or there is a prob really understand the physical propertiesuncertain. of Here, this I state, discuss some an of the recent developmentsa picture is the detection of broad iron features in the X-ray s standing of this state. Overall, it appears that the stronge Speaker. ¡ Copyright owned by the author(s) under the terms of the Creat c ¢ VII Microquasar Workshop: Microquasars and Beyond September 1-5 2008 Foca, Izmir, Turkey John A. Tomsick Space Science Laboratory, 7 Gauss Way, University of Califo Hard (State) Problems USA E-mail: PoS(MQW7)004 4–2.0. ¢ 1 ¡ Γ ff above this John A. Tomsick may be required to feed in ke to answer concerns the R eginnings and at the ends of yg X-1 [37]. There is strong State” by Tomsick et al. (2008) ding of accreting sys- compact jet is always seen in the ) of the optically thick disk. This t, the energy spectrum in the hard scribing the defining properties of be very important for creating the ntire outbursts, and occasionally, a in –258, 1E 1740.7–2942) spend most 27] is an rms noise level of 10%, but oncerning the hard state. Then, I dis- R s a high level of timing noise in the n favor of this picture. Although the raining the disk/jet connection. One entitled “Broadband X-ray Spectra of be some of these recent observations. to be the standard picture for the hard steresis can occur where the transition e optically thick disk and the corona this state can extend to higher energies e hard state for its entire outburst [39]. act jets. For example, the jet may rely occurs at a higher luminosity level that hat a small e hard state as well as some on-going ar-IR [4, 28], and it may extend to even ]. In addition, low-luminosity transients r many observations, some recent obser- ate models. rate, but mass accretion rate is not the only 20–50% [33]. The third defining characteristic

2 5–100 keV bandpass with a photon index in the range

) spectrum often peaks near 100 keV and is exponentially cuto ν F ν The hard state is defined by three main characteristics. Firs One of the main questions about the hard state that we would li For most black hole transients, the hard state is seen at the b This work is devoted to a discussion of our current understan is important for understanding(i.e., the the relationship site between of th thecan imagine hard that X-ray the production) geometry asconditions of necessary well the for as optically the const production thickon of disk matter detectable may coming comp from the optically thick disk, suggesting t from the hard state at thethe beginning transition of to an the outburst hard typically state at the end of the outburst [16 parameter that determines the state of the system because hy (e.g., XTE J1118+480) can remain in the hard state for their e outbursts. It is often seen at relatively low mass accretion high-luminosity transient (e.g., V404 Cyg) canThere remain are in also th several persistent systemsof (Cyg their X-1, time GRS in 1758 the hard state. Although the ( energy [15], some observations suggest that thewithout spectrum a in cutoff [1, 2].X-ray band. The The threshold second value defining formany the characteristic systems hard i show state rms defined noise in levels [ going up to radio band, and itevidence has that been the jet resolved emission for extends to GRShigher the energies. 1915+105 infrared and [5] ne and C is the presence of a steady and powerful compact jet [12]. The tems when they are inthe the hard hard state state. and the In questions that thiscuss we the work, would truncated I like disk to start picture, answer by c whichstate, de most and people I consider present somepicture of is the successful key in observational providing evidencevations a i appear natural to description be fo in conflictOne of with the the recent picture, observations and isGX I presented 339–4 descri our and recent the paper Geometry of[41]. Accreting Black Holes Finally, in I the Hard willwork discuss to provide some observational alternate tests for pictures theoretical for hard th st 2. The Hard State state is a power-law in the accretion geometry — specifically, what is the inner radius ( Hard (State) Problems 1. Overview PoS(MQW7)004 the 3 keV , so its £ ¡ makes its 62 nent found in ¢ R or a change in ¡ ) when systems John A. Tomsick g in b R R , drops from values in kT rom an optically thin region ne system, XTE J1118+480, ), the optical, UV, and X-ray l-described by a disk-blackbody nt” or TD) state to the hard state, Edd perature, ost all systems, when the thermal l. (1997) work does not consider hat are well explained within the L of the emission is in the soft X-ray It was shown that the ADAF model piro, Lightman, & Eardley (1976) component from the optically thick lintock (2008) [31] shows the basic sion incident on the jet, then this can diate state. It only turns on when the his suggests that if the disk remains e this is a good representation of the retion geometry. -ray coverage only includes he observations is the indication of a is viable if advection is considered as extinction is too high to obtain a good s was conceived early-on in the study erent black hole states by allowing for own that, during outburst decay, the jet n the optically thick disk and the jet to is due to a change in on its way to the hard state. To be viable, in kT may be required to avoid cooling the jet. Either 100–1000 gravitational radii, in

3 R ). [11]. Importantly, this model envisions that in R 1.8 kpc, and it is at a high Galactic latitude of 0.3 keV in the hard state [19]. After the drop in temperature,

becomes very large ( in 02 keV. Although different studies which modeled this compo ¢ R 0 ¡ in kT Rossi X-ray Timing Explorer (RXTE) The idea that the hard X-ray emission in the hard state comes f In the following subsections we list several observations t As black hole systems pass from the soft (or “thermal-domina In most cases, it is not clear whether the drop in thermal component is often not detected, especially if the X this model requires that largest changes as it passes through the intermediate state near 1 keV in the TD state to way, it is clear thatbe one a expects significant that one, the making interaction it betwee important to determine the acc 3. The Truncated Disk Picture close to the black holeof while accretion the disks optically thick around diskmodel black recede proved holes to [35]. be unstable, this Althoughin sort Advection-Dominated the of Accretion Sha Flow accretion (ADAF) geometry models [32]. could generally explain the energychanges spectra in seen mass for the accretion diff rate and spectrum was measured, and thecomponent optical with an UV emission was wel are in the hard statethe presence and of in jets, quiescence. a recentADAF Although review version article the of by Esin the Narayan et truncated & disk McC a basic picture. picture, one (I aspect note of thatcompact whil the jet picture in that the does intermediate not state.does match not In t turn fact, on it while has the beensource spectrum sh reaches is its evolving hardest in level the [18].) interme truncated disk picture. 3.1 Changes to the Energy Spectrum the primary emission component changes from beingdisk a to thermal the hard power-lawcomponent component is discussed above. modeled by In a alm disk-blackbody, the inner disk tem mass accretion rate because for mostmeasurement black hole of systems, the the shape of theand thermal component UV since bands. most However,because good it measurements is relatively were nearby, obtained for o extinction is very low. At 0.1% of the Eddington luminosity ( (e.g., the Hard (State) Problems the jet. On the other hand, if there is too much soft X-ray emis cause significant Compton cooling ofrelatively hot the (and jet bright) electrons, that a and relatively t large PoS(MQW7)004 in R 10 Hz to

stems show John A. Tomsick changes from 2.2 to amical time scale at Γ [10, 3, 43], which are isk Picture g R 0.3 as [14, 17, 42, 39, 36], connecting by a factor of 14, so that if

explained by the truncated disk eometry of the system is the re- Γ his is consistent with a truncated in s as black hole systems enter the ween the corona and the optically can be seen as supporting the trun- ation, other possibilities include a R e subtended by the optically thick equency to change from roduced must be photon-starved in ions also seem to find a natural ex- ted disk model is related to the hard ization by a thermal distribution of 1 to it is a possible explanation. e drops during the transition to the ex, y thick disk.

riodic Oscillations (QPOs) and other es [40]. es, there is evidence that characteristic ned by a truncated disk. The example e explanation for the evolution, but the s have pointed out that there is a strong cal changes that might somehow isolate enges to this picture. In part, improved ms, such as the break frequency in the by the time the system reached the hard state. g R 4 . The Compton reflection component consists of a changes from π 2 π

2 Ω

Ω 20 and 100 keV [21] as well as absorption edges and fluorescent

shows a dramatic drop. It was shown that several black hole sy , the values found were between 110 and 700 in π R 2

Ω changes from 2.4 to 1.6. If this frequency scales with the dyn Γ in the TD state, then it would be at 84 g R Another spectral feature that is strongly dependent on the g While the observations described in the preceeding section A second spectral feature that is consistent with the trunca The evolution of the timing properties during state transit An important indication that the accretion geometry change , then such a change in frequency would imply a change in 0.2 Hz as in

Although the QPO is usually notfrequencies detected in continue fainter to hard drop stat in the hard state as flux3.3 decreas Drop in the Strength of the Reflection Component flection component, whose strengthdisk depends as on seen the from solid the angl hard X-ray source, was at 6 very similar changes, specifically, that 1.5 [45, 44]. Itpicture along was with also a shown geometry thatthick where disk this there [44]. evolution is This can some explanationgood be overlap is agreement bet well not between necessarily this a model uniqu and the data indicate that 4. Recent Observations that may Conflict with the Truncated D cated disk picture, some recent observations present chall R consistent with expectations for the truncated disk model. power-law tail. If thiselectrons, emission then is the due corona to whereorder inverse the to Componton hard maintain X-ray a emission temperaturedisk, is as and high p a as truncated 100 keV diskdrop [8]. in seems the to While radiative efficiency be t in the thethe disk most corona or from natural other soft geometri explan X-ray emission produced by the opticall 3.2 Drop in Characteristic Frequencies planation within the truncatedcharacteristic disk frequencies picture. detected Both from Quasi-Pe power black spectrum, hole exhibit syste ahard decrease state as and the in the mass hardcorrelation accretion state. between rat the Furthermore, QPO several frequency group and the power-law ind the timing changes to spectralshown changes in that [39] shows are that well-explai the typical behavior is for the QPO fr bump in the emission bewtween emission lines, most prominently from iron. hard state is that Hard (State) Problems different values for PoS(MQW7)004 ∝

39 ¢ . The enges DBB 0 Suzaku N Edd ¡ L in observations [6] to kT Chandra X-ray John A. Tomsick Swift 0, 34]. The finding , the BeppoSAX rder of magnitude lower, , for Swift J1753.5–0127 and been reports that it persists at [9] to tting thermal disk components hey are consistent with little or nents to constrain the evolution rties of the thermal component ight hard states can exhibit ther- sities than seen previously. For cretion rate rather than a change Edd e well-understood. However, it is L XMM-Newton component in the hard state and the nt with the iron line measurements ge, were re-analyzed accounting for ear how large the systematic error is ASCA . It has also been detected at around 817–330 can show disk temperatures d the color temperature, and changes troduce systematic errors such as the act, when the same disk, it was found that the inner radius o the inner radius according to relationship, implying that any changes ity prescription, electron scattering that ded this new information, including the increases between the two observations. Edd 0.1% [41]. GX 339–4 was also observed at a 4 in L ion of in

T 4 R 012 keV at a luminosity of 2.3% 2 keV, recent observations have shown that ∝ ¢ 10 ¢ 2% 0 0 L ¦

¥

5 7 4 £ £ 200 is much lower than seen in our observation of 2 1 in

¤ ¢ 193 ¢ observations of GX 339–4 in the hard state, we also kT 9 ¢ 0 2 ¡ ¡ ¡ of 700 in RXTE kT DBB DBB and N N when compared with previous satellites. Here, the two chall , and a higher thermal disk temperature was measured, Swift using the thermal disk component. Edd in L Suzaku R 2 keV to much lower luminosities, ¢ , and observations is consistent with an relative to the location of the inner radius in the TD state [3 0 in

R Swift in , Swift kT 20

is that it is difficult to be sure that the systematic errors ar . However, obtaining physically meaningful parameters by fi 0.2 keV while XTE J1118+480 has a disk temperature that is an o Overall, my conclusion concerning using thermal disk compo From modeling these components, it has been suggested that t In our recent work on Although it has long been known that sources in relatively br in in , and we measure a value of

R R 04 keV. However, the value of 2 in ¢ R interesting that sources like Swift J1753.5–0127of and XTE J1 of normalization of the disk-blackbody component is related t this luminosity for GX 339–4a and level GRO of J1655–40, but there have While this could bereported the in case, [41] and this [29] conclusionon and is the discussed measurement below, not and of consiste it is not cl in the case ofduring XTE J1817–330 is that the evolution of the prope XTE J1817–330 [30, 34]. no change in is challenging, and there areassumptions about many the uncertainties inner that boundary condition, cancan the in viscos cause a difference betweento the the effective temperature temperature profile an in the disk due to irradiation. In f that were used to conclude thata the different inner inner radius boundary does condition notcould and chan change irradiation by of as the much as a factor of 10 [13]. detect a thermal disk component at in the thermal disk componentin is related to a change in mass ac higher luminosity, 5.6% 0 GX 339–4 [29], which could be taken as evidence that this component is present in more sources and at lower lumino Hard (State) Problems X-ray instrumentation over the past several years has provi better soft X-ray sensitivity and/or better energy resolut Cyg X-1, this component has been detected by satellites from Observatory [24] when the source has been at a luminosity of mal disk components with temperatures of we describe and discuss are measurementsbroad of iron the features thermal in disk the reflection component. 4.1 Thermal Disk Components PoS(MQW7)004 g 4 0 £ £ 1 1 R atio ¤ ¢ plus 5 ¢ 6 ¢ RXTE 0 1]. Our

, and the 0 and ¢ Edd L John A. Tomsick Swift while 5 XMM-Newton g R ed the 5 ¢ 0 , either the truncated disk is constrained to be 3

Edd , than the earlier observation. 0 hat have used the most recent in ¢ tion of broad iron features in vel of activity, but the amount L R still worthwhile. Edd not simply restricted to GX 339– dence for broad iron features, and ction to what is expected for the data from 2004. The observation L ibe results that have been obtained uminosities, the hard state has not e results of the that t the disk extends very close to the ausing Doppler shifts, as well as by 2.3% ine studies that use higher resolution f the Compton reflection component, istance of 8 kpc for GX 339–4 and a though such features have been seen observation described above), and the “CDID” model). The result is that the ion features. h 3 separate outbursts. The first study ly high luminosity, 5.6% e relativistic effects. The main source is that they are relativistically smeared lable with the current generation of X- observations were carried out at the end RXTE el in XSPEC) and two different reflection iron features have also been reported for over the past few years. We note that in and . Even if this does not give a clean measurement 6 RXTE Edd is constrained to be 4 L XMM-Newton in R , and . The spectrum at the higher luminosity level is shown in 0.1% XMM-Newton

Edd Swift L , Proportional Counter Array (PCA) light curve and hardness r spectra also show strong evidence for broad iron features [4 at 0.8% g R RXTE RXTE 10 XMM-Newton

and and Swift Edd L spectral analysis are reported in [29]. The spectra show evi , efforts to improve our understanding of this component are observations occurred at lower luminosity, 2.3% and 0.8% The second challenge to the truncated disk model is the detec A separate study of GX 339–4 was carried out by our group. We us Figure 1 shows the Although GX 339–4 is the only system with published studies t in at 2.3% R g models (“pexriv” and the “constant density ionized disk” or RXTE they are fitted with relativistic smearing (the “kdblur” mod smearing of the ironblack features hole. is With strong the enough first reflection to model, require tha result using the pexriv reflection model smeared by kdblur is picture is wrong or we are mis-interpreting the broad reflect hardness ratio shows that the system was in the hard state. Th Even so, the 4.2 Broad Iron Features in the Hard State the hard state. Asand discussed the above, leading these interpretation features for areby the part motion width o of of accretion the disk features redshifts material caused around the by black the hole,in black c several hole’s Galactic gravitational black field. holebeen systems as Al when well-studied with they the areray higher at satellites. energy high resolution However, l avai there areinstrumentation now along a with few hard spectral state modelsthat iron has that l been include studied in th this wayfor is GX this 339–4, source and here with we descr of is obtained with the CDID model. deriving the Eddington-scaled luminosities, weblack assumed hole a mass d of 5.8 solar masses. Cyg X-1 [24] and for XTE J1650–500 [7]. Thus, the features are Figure 2. instrumentation and relativistic reflection models, broad 4. For GX 339–4,truncated the disk small model, and inner this radii implies derived that, are at in least contradi down to observations marked in Figure 1, and itof is the notable that 2007–2008 these outburst (in contrastSwift to the R Hard (State) Problems 0.02 keV at the same luminosity level, for GX 339–4 from 2004–2008.of The activity system over normally this has 4 aof year high iron period le features is was exceptionally carried high out wit using occurred at the start of the 2004–2005 outburst at a relative PoS(MQW7)004

obser- 4400 Swift John A. Tomsick Swift

Rossi X-ray Timing 4200 Observations 2007-2008 Outburst

4000 essarily incompatible with the tions with the and it is worthwhile to consider n inner cool disk remains in the rate outbursts were detected between jet is fed by an ADAF. However, a observation in 2004 and two vations than the truncated disk model.

3800 7

XMM-Newton 3600 MJD-50000 (days)

3400 RXTE/PCA Observations of GX 339-4 of GX Observations RXTE/PCA

2004-2005 Outburst 3200 XMM Observation

1 3000 10 0.2 0.0 0.1 1.2 1.0 0.8 0.6 0.4

100 GX 339–4 light curve and hardness ratio from pointed observa -0.2

1000 ’s Proportional Counter Array (PCA) instrument. Three sepa Hardness (9.8-25 keV)/(2.8-5.2 keV) keV)/(2.8-5.2 (9.8-25 Hardness PCA rate (2.8-25 keV) (2.8-25 rate PCA Other hard state accretion geometries have been suggested, First, it should be noted that the compact jet model is not nec Figure 1: Hard (State) Problems vations in 2007. 5. Some Alternate Pictures whether they may provide a betterHere, explaination for I the will obser consider ahard state. compact jet model and a picture where a 5.1 Compact Jet Model truncated disk picture since it is possible that the compact Explorer 2004 and 2008. The vertical dashed lines mark an PoS(MQW7)004 as in [26, 28], g R John A. Tomsick 100 applied to hard state Spectral HEXTE the broadened iron features, it s for Cyg X-1, GX 339–4, and 005) [26], then this would give a eter in the model is the “nozzle e broad iron features would have ranged from 3.5 to 9.6 Power-law tral model, this parameter is related d explain the broad iron features. Reflection Component y thin synchrotron emission, and it has raction of the X-ray emission came from . The figure has been adapted from Tomsick et of the black hole while the jet is also launched 10 g Iron Line PCA R 8 Energy (keV) . The model components are shown, and we focus on the thermal that are derived from the relativistic reflection models. Edd L in R Disk energy spectrum of GX 339–4 taken in 2007 May when the source w Thermal 1 RXTE Swift/XRT and 1 Swift 0.1 0.01

The

0.001

E (keV cm (keV F E ) s

-1 -2 However, even if such a picture appears to be consistent with In fact, the Markoff et al. [26] compact jet model has now been which is similar to the values of and collimated in this region. In addition, if a significant f the base of the jet asreflection envisioned component by from Markoff, the Nowak, inner & part Wilms of (2 the disk that coul Energy Distributions for aradius,” few which black is hole the systems. radiusto of the the One location base param of of the thebeen break jet. relatively from optically well-constrained In thick the by to spec GRO some opticall J1655–40 SEDs. have been fitted, When values the for this SED parameter have disk component and the broad reflection features in this work al. (2008) [41]. version of the compact jet model that may be able to explain th the optically thick disk extending within several the hard state at a luminosity of 2.3% Figure 2: Hard (State) Problems PoS(MQW7)004 1–0.4, ¢ 0

50 to a few parameter).

α α John A. Tomsick , Markoff & Nowak π [41], it was shown that 2

Edd Ω L l to observations by deter- disk component in the hard e exponential cutoffs near this onents seen in GX 339–4 and . Concerning the shape of the cently is the idea that an inner hen the mass accretion rate be- accretion rate drops during the tting compact jet. π ue for 2 rd X-ray spectra where the cutoff ristic frequencies. Although some 7 observations of GX 339–4 with a e spectra, but it would be useful to

onounced [22]. Thus, not only is it p in this parameter as sources make ristic frequencies, it is currently an the marginally stable orbit (i.e., 1–6 ona and conduction of that heat into he hard X-rays illuminating the inner ission, when Compton cooling of the ectra always have an cutoff near 100 he disk should occur at a luminosity he jet will be relativistically beamed Ω ate should actually be at parameters in the range n the broadened iron lines. Since the rate. The calculations of [23] and [38] served. However, it is not clear if the y to carry out. at calculations predict should happen. dge of the disk. However, calculations trength of the reflection component, the y in the corona, i.e., the in the model, reflection from that region isions that material from the optically thick 31, an Eddington-scaled mass accretion rate of ¢ . 0 9 g R ¡ α 203 keV and a luminosity of 2.3% ¢ 0 ¡ eff T . Edd L Finally, it is a prediction of the inner cool disk model that w While it has been shown that the model can explain the thermal Recently, [23] and [38] have applied the inner cool disk mode Another possibility that has been explored in some detail re , depending on the black hole’s spin) to 142 g comes low enough the entire inner disksuggests will that eventually evapo the complete evaporationnear of 0.1% the inner part of t geometry of the hard X-ray source ispart consistent of with the most disk. of This t would be a very useful theoretical stud should certainly produce the broad iron features that are ob state, it has not yetoptically been thick determined disk whether extends it to could the marginally explai stable orbit the observations could be reproduced with the thermal disk components could bethermal reproduced. disk temperature For of the 200 6.87%, and an inner optically thick cool disk extending from have argued that such a picture would lead to a much higher val hundred gravitational radii (depending mostlySince the on inner viscosit disk has thecorona strongest is level also of accounted soft for, photonpossible the em for effect a becomes inner even cool more disk pr to remain, but it is actually wh R shape of the hard X-ray spectrum, and the changes in characte Hard (State) Problems is still necessary to ask whether it can explain the overall s (2004) [25] have shown that thetransitions model to is consistent the with hard a stateaway dro because from the the X-ray optically emissionX-ray thick in spectrum, disk, t it explaining is the importantkeV to drop or determine in not. if black However, hole weenergy sp do [15]. know The that compact thedetermine jet spectra model if sometimes does the hav predict model cutoffsshape can in has specifically th been predict very some well-measured. ofopen question the Concerning whether ha the QPOs would characte be expected for an X-ray emi 5.2 Inner Cool Disk Picture optically thick disk cantransition remain to the in hard state, the the truncated harddisk disk will picture state. env evaporate into the As coronaby the starting [22] from mass that the account inner for e the viscous optically generation thick of disk show heat that in the the maximum evaporation cor r mining whether the modelSwift can J1753.5–0127. reproduce In the fact, it thermal was disk found comp that for viscosity PoS(MQW7)004 g of orts in host- John A. Tomsick . In particular, we Guest Observer grants Swift , and RXTE y have programs to try to extend rvations are telling us that there ny contributions from my collab- d wing of the iron line could be r interpretation of the broad iron entific Organizing Committees for tter densities that are assumed are mal motions and higher ionization Suzaku lei (AGN). Some inaccuracies may 20]; however, it is still not clear if ctral states: Soft (or TD) and hard. nterpretation for the broad iron fea- lem down to 0.1%, the evidence that use of the way it deals with higher , owledge useful discussions with par- aret, Sera Markoff, Simone Migliari, the broad iron features. Guest Observer grant NNX08AQ60G. odel specifically for stellar mass black se, the models mentioned above (pexriv 543, 373 of the hard state. Also, it has been men- quate for the case of stellar mass black om NASA er, C. R., & Cui, W., 2003, MNRAS, 346, observation of GX 339–4 at a significantly Swift study. It will be very interesting to see if we find 10 XMM-Newton Suzaku While thus far, the observations only indicate a problem RXTE and , there are strong implications for our entire understandin Edd Swift L 1%

I would especially like to thank Emrah Kalemci for all his eff 689 Thus, it is very important to determine if the relativistic i Also, more can be done on the observational side. We currentl Acknowledgements The most important point is that it really seems like the obse [4] Corbel, S., & Fender, R. P.,[5] 2002, ApJ, Dhawan, 573, V., L35 Mirabel, I. F., & Rodríguez, L. F., 2000, ApJ, [1] Belloni, T., et al., 2006, MNRAS,[2] 367, 1113 Caballero-Garcia, M. D., et al., 2007,[3] ApJ, 669, Chaty, 534 S., Haswell, C. A., Malzac, J., Hynes, R. I., Shrad the differences between the mostAlthough the fundamental thermal black disk component hole may spe alsothis indicate component a requires prob a non-truncated disk is weaker than tures is the onlyexplained viable by one. Compton down-scattering It ofthis has model the can been line simultaneously emission explain suggested the [ that other properties the re the hard state studies to lower luminosities with tioned that it is not clear if the relativistic models are ade holes. Although they are often applied toand the CDID) stellar were mass ca originally developedbe for Active present Galactic when Nuc usingionizations. pexriv for While hotter the accretion CDIDstates) disks model in beca deals a with hot much disks improvedappropriate (ther for manner, AGN. it Developing is a relativistic stillholes reflection would true m be that a the positive step. ma recently (2008 September) carried out a 100 ks lower luminosity than the [41] ing this workshop. I wouldhelping also to like make to the thank meeting theorators, a Local including great and Stephane success. Sci Corbel, I Emrah acknowledgeRob Kalemci, Fender, ma Phil Charles Ka Bailyn, and Michelle Buxton.ticipants I of also the ackn workshop. I acknowledge partial support fr any change in the broad iron features. Hard (State) Problems 6. Summary and Future Work is a problem eitherfeatures with for the black holes truncated in disk thedown picture hard to state. or a with luminosity ou of References NNG06GA81G and NNX06AG83G and from NASA PoS(MQW7)004 John A. Tomsick ersity Press), 157 Compact stellar X-ray view, 51, 733 03 ., 1996, ApJ, 467, 419 , 352, 182 al Studies of Black Hole X-Ray Transients pJ, 204, 187 489, 865 ., 2007, ApJ, 671, 695 own, K., Skibo, J. G., & Phlips, B. F., 1998, binaries”, , L113 P., 2007, ApJ, 666, 1129 R. E., Pottschmidt, K., Corbel, S., ad, R. W., Wijnands, R., Charles, P. A., & ., Haswell, C. A., Hynes, R. I., & Muno, , E., & Kawaguchi, T., 2002, ApJ, 575, 117 midt, K., & Kaaret, P., 2004, ApJ, 603, 231 11 ˙ Zycki, P. T., Burderi, L., & Robba, N. R., 2001, ApJ, 547, 1024 ´ nski, M., 2006, MNRAS, 367, 659 ´ nski, M., & Kubota, A., 2007, A&A Rev., 15, 1 Edited by Walter Lewin & : Cambridge Univ ´ nski, M., Done, C., & Page, K., 2008, MNRAS, 388, 753 During Outburst Decay” Brocksopp, C., & Kaaret, P., 2005, ApJ, 622, 508 ApJ, 500, 899 sources. Fabian, A. C., 2006a, ApJ, 653, 525 M. P., 2001, ApJ, 555, 483 [7] Done, C., & Gierli [6] Di Salvo, T., Done, C., [8] Done, C., Gierli [9] Ebisawa, K., Ueda, Y., Inoue, H., Tanaka, Y., & White, N. E Hard (State) Problems [14] Gilfanov, M., Churazov, E., & Revnivtsev, M., 1999, A&A [18] Kalemci, E., Tomsick, J. A., Buxton, M. M., Rothschild, [19] Kalemci, E., Tomsick, J. A., Rothschild, R. E., Pottsch [15] Grove, J. E., Johnson, W. N., Kroeger, R. A., McNaron-Br [20] Laurent, P., & Titarchuk, L., 2007,[21] ApJ, 656, 1056 Lightman, A. P., & White, T. R.,[22] 1988, ApJ, Liu, 335, B. 57 F., Mineshige, S., Meyer, F., Meyer-Hofmeister [24] Makishima, K., et al., 2008, PASJ,[25] 60, 585 Markoff, S., & Nowak, M. A.,[26] 2004, ApJ, Markoff, 609, S., 972 Nowak, M. A., &[27] Wilms, J., 2005, McClintock, J. ApJ, E., 635, 12 & Remillard, R. A., 2006, “Black hole [32] Narayan, R., & Yi, I., 1994,[33] ApJ, 428, Pottschmidt, L13 K., et al., 2003, A&A,[34] 407, 1039 Rykoff, E. S., Miller, J. M., Steeghs, D., & Torres, M. A. [16] Homan, J., & Belloni, T., 2005,[17] Ap&SS, 300, Kalemci, 107 E., 2002, Ph.D. Thesis (UC San Diego), “Tempor [23] Liu, B. F., Taam, R. E., Meyer-Hofmeister, E., & Meyer, F [31] Narayan, R., & McClintock, J. E., 2008, New Astronomy Re [35] Shapiro, S. L., Lightman, A. P., & Eardley, D. M., 1976, A [30] Miller, J. M., Homan, J., & Miniutti, G., 2006b, ApJ, 652 [28] Migliari, S., et al., 2007, ApJ,[29] 670, 610 Miller, J. M., Homan, J., Steeghs, D., Rupen, M., Hunste [12] Fender, R. P., 2001, MNRAS, 322,[13] 31 Gierli [11] Esin, A. A., McClintock, J. E., & Narayan, R., 1997, ApJ, [10] Esin, A. A., McClintock, J. E., Drake, J. J., Garcia, M. R PoS(MQW7)004 , eds. P. 55 John A. Tomsick AS, 303, L11 ., 2008, arXiv:0807.3402 [astro-ph] , 439 tt, M. A., Fender, R. P., & Ogley, R. N., 2001, X-Ray Timing 2003: Rossi and Beyond van der Klis, M., 2003, A&A, 397, 729 12 ´ nski, P., Gilfanov, M., & Revnivtsev, M., 2003, MNRAS, 342, 3 Kaaret, F. K. Lamb, & J. H. Swank, astro-ph/0401189, 71 MNRAS, 327, 1273 [41] Tomsick, J. A., et al., 2008,[42] ApJ, 680, 593 Vignarca, F., Migliari, S., Belloni, T., Psaltis, D., & [40] Tomsick, J. A., Kalemci, E., & Kaaret, P., 2004, ApJ, 601 [43] Yuan, F., Cui, W., & Narayan, R.,[44] 2005, ApJ, Zdziarski, 620, A. 905 A., Lubi [45] Zdziarski, A. A., Lubinski, P., & Smith, D. A., 1999, MNR Hard (State) Problems [36] Shaposhnikov, N., & Titarchuk, L., 2007,[37] ApJ, 663, Stirling, 445 A. M., Spencer, R. E., de la , C. J., Garre [39] Tomsick, J. A., 2004, in Proc. of AIP Conf. Proc. 714: [38] Taam, R. E., Liu, B. F., Meyer, F., & Meyer-Hofmeister, E