Baribaud/PelatiPhillips, Acker/Stenholm/Lundström, Alloin/Baribaud/PelatiPhillips,BertolaiBusonNietri, Vettolani/Fairall/DaCostaiChincarini, Drechsel/Andreae, Dan­ziger/Fosbury/Lucy/Wampler, Courvoisier/Bouchet.

1.4-m CAT

October 1987: Solanki/Mathys, Holweger/Gigas/Lemke, Gratton, Spite F./Spite M.

November 1987: Spite F./Spite M., Ben­venuti/Porceddu, Waelkens, Lagrange/Fer­leWidal-Madjar, FerletiAndreani/Dennefeld/Vidal-Madjar, Andreani/FerleWidal-Madjar/Grenier, FerleWidal-Madjar/Gry/Lallement,Lagrange/FerleWidal-Madjar, Barbuy/Ar­nould/Jorissen.

December 1987: Barbuy/Arnould/Jorissen,Grenon/Barbuy, Pottasch/Sahu, Barbuy,Pallavicini/Giampapa, Stahl/SchwarzIWolf/Zickgraf, de Vries/van Dishoeck/Habing,Stahl/SchwarzIWolfiZickgraf.

January 1988: ReimerslToussaintiSchröder, Stahl/SchwarzIWolf/Zickgraf,Gustafsson/Edvardsson/Magain/Nissen,Gustafsson/SaarNilhu, Cayrel de Strobel.

February 1988: Cayrel de Strobel, Vladilo/Beckman/Crivellari/Molaro, GilletiPelat,Lundgren, Lenhart/Grewing/Neri.

March 1988: Lenhart/Grewing/Neri, Vreux!Magain.

1-m Photometrie Teleseope

October 1987: Hesselbjerg Christensen,Johansson/Bergvall, BöhnhardWanysek/BeiBer, Di Martino/ZappalaiCellino/Farinella,WolfiStahl/Davidson/Humphreys.

November 1987: WolfiStahl/Davidson/Humphreys, Catalano F.A./Kroll, Liller/AI­caino, Bues/Pragal, Bues/Müller/Rupprecht,Chini/Krügel.

December 1987: Chini/Krügel, Heske/Wendker, Courvoisier/Bouchet, Busso/Sil­vestro/Scaltriti/Persi/Robberto, MattilalSchnur, Barucci/Fulchignoni/Harris/ZappalalBinzel/Di Martino/LagerkvistiBurchi/Dipao­loantonio, Lyngä/Johansson.

January 1988: Lyngä/Johansson, Cour­voisier/Bouchet, Kaelble/Kappelmann/Grew­ing, Le Bertre/Epchtein, Reipurth/Zinnecker,

Spinoglio/Persi/Coe/Ferrari-Toniolo, Wester­lund/Pettersson, Balkowski/Arimoto/Bois­son/Durret.

February 1988: Balkowski/Arimoto/Boisson/Durret, The/WesterlundNardya,GreenberglThe/Chlewicki, Courvoisier/Bouchet, Le Bertre/Epchtein, Schoembs/Barwig/Mantel, Poulain/DavoustiNieto, Ko­houtek/Martin.

March 1988: Kohoutek/Martin, Le Bertre/Epchtein, Courvoisier/Bouchet, Mermilliod/Claria, Antonello/Conconi/MantegazzalPoretti, Moneti/Stanga.

50-ern ESO Photometrie Teleseope

October 1987: Group for Long TermPhotometry of Variables.

November 1987: WolfiStahl/Davidson/Humphreys, Poretti/Antonello, Pospieszals­ka-Surdej/SurdejlTaylor, Cutispoto/Rodono/VenturaiCatalano F./Butler.

December 1987: Cutispoto/RodonoNen­turaiCatalano F./Butler, MattilaiSchnur.

January 1988: Debehogne/Di Martino/ZappalaiDe Sanctis/LagerkvistiMagnusson,Waelkens/Cuypers.

February 1988: Waelkens/Cuypers, Th81WesteriundNardya, GreenberglThe/Chlewic­ki, Kohoutek, BarreraiMennickenWogt.

March 1988: BarreraiMennickenWogt,Group for Long Term Photometry of Vari­ables.

GPO 40-em Astrograph

October 1987: BöhnhardWanysek/BeiBer.November 1987: Scardia.January 1988: Debehogne/Machado/Cal-

deiraNieiraiNetto/ZappalaiDe Sanctis/La-gerkvistiMourao/Protitch-Benishek/Javan­shir.

February 1988: ElstilvanovalShkodrov/Geffert, Mermilliod/Heudier.

March 1988: Ferreri/ZappalaiDi Martino/De Sanctis/Debehogne.

1.5-m Danish Teleseope

October 1987: Gammelgärd, J0rgensen etal., Hansen et al., Helmer et al., Lindgren/Ardeberg.

November 1987: Lindgren/Ardeberg,Griffin R. F./Griffin R. E. M./Mayor/Clube, Im­bert, Imbert/Maurice/PrevotiAndersen/Nord­ström/Ardeberg/Lindgren/Mayor, Richtier,LeibundgutITammann, Noergaard-Nielsen/Hansen/Joergensen, SauvageotiDennefeld,Alcaino/Liller, JÖnch-S0rensen/J. Knude.

December 1987: Jönch-S0rensen/Knude,Reipurth, Jönch-S0rensen/Knude, Becker/Appenzeller/Wilson/Schulte-Ladbeck.

January 1988: Becker/Appenzeller/Wilson/Schulte-Ladbeck, Gouiffes/Cristiani, Giraud,Melnick, Della Valle/Rosino/Ortolani/CappellarolTuratto, Westerlund/Pettersson,v. Paradijs/v. d. Klis/Charles, Andersen/Nord­ström.

February 1988: Anderson/Nordström, M01­ler/Rasmussen, Hansen et al., Reiz et al.,Andersen/Nordström/Mayor/Olsen.

March 1988: Andersen/Nordström/Mayor/Olsen, Lindgren/Ardeberg, Mayor/Du-quennoy/Andersen/Nordström, GallettalBettoni, Ortolani/Piotto, Ortolani/Gratton.

50-ern Danish Teleseope

October 1987: Olsen, Grenon/Lub.November 1987: Grenon/Lub, Lindgren/

Ardeberg.December 1987: Lindgren/Ardeberg,

Group for Long Term Photometry of Vari­ables.

January 1988: Group for Long Term Photo­metry of Variables, Olsen/Gray.

February 1988: Olsen/Gray, PellegattiFranco, Lindgren/Ardeberg, Clausen et al.

March 1988: Clausen et al., HeltiClausen/GimenezNaz.

90-em Duteh Teleseope

November 1987: Grenon/Lub, v.Amerongen/v. Paradijs.

December 1987: v. Amerongen/v. Paradijs.January 1988: de Geus/Lub/Blaauw/de

Zeeuw, de Ruiter/Lub, de Loore/David/Blaauw/HensbergeNerschueren, de Ruiter/Lub, The/WesterlundNardya.

February 1988: The/WesterlundNardya.March 1988: Heynderickx, Caspers,

Brand/Wouterloot.

IC 3370: a Box-Shaped Elliptical or SO Galaxy?B. JARVIS, Observatoire de Geneve, Switzerland

I. Introduction

It has now been established that asignificant portion (~ 1 per cent, Jarvis1986) of disk galaxies have box- orpeanut-shaped bulges. However, untilfairly recently, it was generally believedthat no elliptical galaxies existed whichpossessed these same box- or peanut­shaped characteristics. If such ellipti­cals do exist, then they would be inter­esting for several reasons. The May etal. (1985) models for box- and peanut-

shaped bulges required a large amountof rotation in order to support theseshapes. However, we know that mostbright elliptical galaxies (MB ~ -21.0)rotate slowly. Hence, a possibledichotomy may exist if bright box- orpeanut-shaped "elliptical"-like (i. e. nodisk) galaxies could be found which ro­tate as rapidly as the current modelsrequire. Such galaxies mayaiso provideimportant formation, evolutionary anddynamical links between classical ellip-

tical and disk galaxies. Fairly recently,several galaxies classified in the litera­ture as ellipticals have indeed beenfound which do show strong box-likefeatures. We report here some of themost interesting results of one of thesegalaxies, IC 3370.

The southern galaxy IC 3370 isclassified as an E2pec in the RevisedShapley Ames Catalogue of BrightGalaxies and an E2 in the Second Re­ference Catalogue of Bright Galaxies.

15

Figure 2.

..IC 3370 also shows a significant

amount of isophotal twisting amountingto a total rotation of about 250 betweenr = 0" and r = 70". This is quite puzzlingin the light of our current understandingof the bulges of disk galaxies especiallyif the "bulge" is close to edge-on asdiscussed below. Classical bulges aregenerally believed to be nearly oblate(eg. Jarvis and Freeman, 1985) in whichcase no isophotal twisting should beobserved at any inclination. Isophotaltwisting in galaxies is most commonlyinterpreted as due to triaxiality. Thelarge change of PA observed in IC 3370is more akin to what is seen in someelliptical galaxies than in the bulges ofdisk galaxies. We may be forced to re­sort to some external process to explainthis twisting such as the merger of twoor more parent galaxies which simul­taneously formed the box shape (seediscussion below). Alternatively, we maybe observing the effect of a past tidalinteraction much like what NGC 205 isundergoing today.

111. Kinematie ObservationsMost of the long-slit spectroscopic

data for IC 3370 were obtained with theBoiler and Chivens spectrograph andCCO at the ESO 3.6-m telescope. Typi­cal exposure times for each slit positionwere 2 hours using a 2" slit and a spec­tral resolution of about 2.4 A. Spectra ofseveral early K-type giant stars werealso observed to form a template formeasuring the galaxy velocity disper­sions and rotation. The geometrie stabil­ity was very good with a total shift ofless than 0.2 pixels (20 km S-1) over fivehours of hour angle. The reduction pro­cedures for long-slit spectroscopic datafollowed standard procedures and willnot be discussed further here. The ve­locities were determined by cross­correlating the galaxy spectra with thestandard star spectra. The observedvelocities V and velocity dispersions 0

along the various cuts in IC 3370 areshown in Figure 4. An internal consis­tency check on the data was made fromthe points where the slit positions in­tersected. These points, plotted as plussigns gave two independent measure­ments for the velocity and velocity dis­persion. An external check on the instru­mental setup and reduction procedureswas afforded by obtaining a short expo­sure of the major axis of the brightgalaxy NGC 4594 and comparing theobserved rotation curve with that ob­served by Kormendy and Illingworth(1982). The results, shown in Figure 5,indicate a good agreement. It is interest­ing to note that the sharp turnover in therotation curve at about 5" on either sideof the nucleus was not seen in the KI orFaber et al. (1977) data.

80 100

Je 3370 Parallel Profiles (0)

o 20 40 60

Radius

42

Figure 3.

18 0"

22

Both the major and minor axisluminosity profiles in all colours are weilfitted by a de Vaucouleurs r~ law, similarto what is observed in "normal" ellipti­cals and the bulges of most disk galax­ies. However, the minor axis luminosityprofile shows a very steep decrease ofluminosity with radius: IB oe Z -44±0.2.

Most ellipticals have indices closer tothat of a Hubble law (I oc [1. Figure 3shows the perpendicular luminosity pro­files of IC 3370 at selected distancesfrom the minor axis as labelIed on theplot. Apart from the 0" cut (minor axis)which closely follows an r ~ law as notedearlier, the remaining perpendicular pro­files are different and are unlike bothclassical spheroidal bulges and normalelliptical galaxies. All show a remarkablyconstant luminosity for z< 50", espe­cially the 50", 60" and 70" cuts beforesharply decreasing, strongly indicatingthe box-shaped nature of the isophotes.

The total magnitude of IC 3370,uncorrected for galactic absorptionis Br = 12.02 ± 0.10. Assuming a dis­tance of 54.1 h-1 Mpc (h = Hol50 km.s-1.Mpc-1

) for IC 3370, the abso­lute B magnitude is MB =-22.1. Few ifany bulges are known which are sig­nificantly more luminous than IC 3370.This luminosity is more typical of ellipti­cal gaJaxies.

shape extends over more than 3.5 mag­nitudes of surface brightness to the faintlimit of the photometry (J.tB = 25.0 magarcsec-2). Moreover. Figure 2 stronglysuggests that the trend of extreme"boxiness" extends to much greater dis­tances and hence lower luminositiesthan can be seen within the CCO field.. .,

~.+.....•

••

•o-----t :

Figure 1.

The ESO/SERC J Survey (see Fig.1)shows JC 3370 as a moderately brightelliptical galaxy with a "bow-tie" or"crossed-streamers" appearance notunlike the peanut-shaped bulge ofNGC 128. On the shallower ESO B sur­vey, IC 3370 resembles anormal ellipti­cal galaxy.

.. . '

.Ie .3370

11. Photometrie Observations

The Johnson B, V and R surfacephotometry of IC 3370 was obtainedwith an RCA CCO (512 x 320 pixels)aligned E-W at the f/13 Cassegrainfocus of the 0.9-m telescope at C.T.1.0.with an image scale of 0.495 arcsecpixel-1

. The raw data frames were re­duced in the standard manner for CCOobservations using the ESO MIOAS sys­tem. Figure 2 shows the isophotal con­tour map of IC 3370 on the Johnson Bmagnitude system. The V and Risophotal maps are very similar. Themost important feature to note is thestrong box shape of the isophotes. This

16

Minor Axis

-

-

I

-I

T

I

T

I

•

I

• • •

IIIo

o

o

o,~:: ..: ....o ••,,,,,

of- - - -;. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _- _I I I I

200 -

100 c-

300-

Of- - - -;. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --I I

Major Axis

! I I I I I I I

300r- 0 -,,,200 r- , I. -

,...-. •a : • ... -+• a+ •••lOOf- -

o 10 20 30

I I I I I I I I

~- -

O---~----------------------------------I I I I I

o 10 20 30

-

-

I

-I I I I I III,,,o

o

oI,,,,II

of- - - -t -.-- _Il -. - ._- - - - - - - '!. - - - - - - - - - - -I • I 1 1 I- 1 1

IOOr-

200f-

300 f-

v-

-••••+ •••.... +.

.-' .

200 -

100-

v

r (..rcaec)

10".1

I I I I I I I I

300 - 0 -0

0

0

0

200 c-o -,o • • • • •a ,..-. • •

100 - ! -

O~---~·_----------------------------------I I I I I I I II I I I I I I I

~f- 0 _

• (arcsec)

15" J.

! 1 I I I I 1 I

300 - 0 -0

0,200 -

, -,,a .. --100- • TT -

,,I

0- - - - :- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -I I I I I I I 1! I I I 1 1 1

~- 0 ­

o

200 f- , -0

V 0

0

100- I .... • • -".. .. • •• • • •• •• •

0

200-0 -0

0

v 0

0

100- +.- • • • - -•t •0- - - - :- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

I I I I I I I I

o 10 20 30

• (..rcace)

Of- - - -'- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --; 1 I

o 10 20 30

• (..rcaec)

Figure 4.

Evidence for a stellar disk in Je 3370

Figure 6 shows the inner 20" ofIC 3370 divided by the same image spa­tially filtered with a circular Gaussianfilter of FWHM = 4.9". We can clearlysee a faint luminous stellar disk totallyenveloped within a much more luminousbulge. The disk is also convincingly re­vealed by least-squares fitting ellipsesto the isophotes of the inner 20" ofIC 3370. This argues in favour ofIC 3370 being an SO pec galaxy and notan E galaxy by classical definition. Thelarge aspect ratio of the disk suggeststhat IC 3370 is seen very nearly edge­on. Moreover, all the Jarvis (1986) sam­pie of 41 disk galaxies with box- orpeanut-shaped bulges also had inclina­tions greater than about 80°. This can

be no coincidence. Therefore we con­clude that the presence of an observ­able box shape with an observableluminous high aspect ratio disk sug­gests an inclination for IC 3370 ofi ~ 80°.

The observed heliocentric velocity ofIC 3370 was measured to be2959 ± 30 km S-1. The inner 7" ofIC 3370 along the major axis is ratatinglike asolid body, reaching a maximunvelocity of about 100 km S-1. Beyondthis point the rotation curve is quite flat.The minor axis rotation curve shows nosignificant mean rotation and indicatesthat IC 3370 is not tumbling.

The kinematically most interestingcuts are those perpendicular to the ma­jor axis and offset from the minor axis atdistances of 10" and 15" fram the nu-

cleus. These are also shown in Figure 4.Their most striking feature is the nearconstancy of the velocity and dispersionwith z to z - re (8h-1 kpc) for the 10" .1cut and z - 0.6re (4.8h-1 kpc) for the 15".1 cut. Therefore, le 3370 is stronglycylindrically rotating to large z distancesabove and below the plane of rotation.In fact, it is cylindrically ratating to sig­nificantly greater z distances than havebeen observed before in disk galaxieswith box- or peanut-shaped bulges.

IV. Implications for Formation

A natural question arises as to howthese galaxies formed. What evidence isthere to suggest that IC 3370 had amostly dissipative formation much likedisk galaxies or alternatively, a weak

17

ReferencesBinney, J., and Petrou, M. (1985). Mon. Not.

R.Asifon. SOG. 214,449.Faber, S. M., Baliek, B., Gallagher, J. S., and

Knapp, G. R. (1977). Astrophys. J. 214,383.

Jarvis, B.J. (1986). Astron. J. 91,65.Jarvis, B.J., and Freeman, K.C. (1985). As­

uophys. J. 295, 314.Kormendy, J., and Illingworth, G. (1982), As­

trophys. J. 256, 460 (KI).May, A., van Albada, T.S., and Norman, C.A.

(1985). Mon. Not. R. Astron. SOG. 214, 131.

Figure 6.

strongest supporting evidence for this isthe discovery of a faint luminous stellardisko

2. IC 3370 is highly cylindrically rotat­ing to much greater z distances thanhave previously been observed in box­or peanut-shaped bulges.

3. The kinematic data show thatIC 3370 has as much rotation as anoblate isotropic model flattened by rota­tion alone.

4. There is an unusually large amountof isophotal twisting in the bulge ofIC 3370 amounting to a total shift ofabout 25°. Merger or tidal processesmay offer the only satisfactory explana­tion for its occurrence.

5. The bulge of IC 3370 is very lumi­nous with MB = - 22.1, making it one ofthe most luminous bulges known.

100

-

50

I

Ne 4594 Major Ä.-'Xis

T •.'f--r-"'..... ..

T- ••.....- .~ ~ ..

• :/' -l' ••

I

I

I

in view of the large amount of isophotaltwisting observed. Slightly triaxial or ob­late elliptical galaxies with an approxi­mately axisymmetric potential cannotbe excluded however. Thus it seemsthat the most likely merger possibility forJC 3370 proposed by Binney and Petrouis the slow collision of two massive diskgalaxies which have appropriately in­c1ined total angular momentum vectors.The absence of a significant amount ofdust in IC 3370 would tend to argue infavour that the merging progenitorswere SO galaxies unless the merger pro­cess triggered efficient star formationdepleting nearly all of the gas. Theseproposals have no sound physical basisat present and can only be tested byadequate n-body experiments.

v. Conclusions

The main conclusions reached in thisstudy of IC 3370 are as folIows:

1. IC 3370 is an SOpec galaxy and notan elliptical as previously classified. The

oR dius ( I"CS cs)

I-50-100

• T• ..: iiI •• ' -". 'Jf

200 r-. _.: _. . ..: ... ".j ..

"'. '"....rr# .~ .~

-' 0

Ul

E~

>. 0....,'u0Q)

>

Figure 5.

dissipative history as is generally be­lieved for the bright ellipticals? Thesmall colour gradient in IC 3370 arguesagainst a strongly dissipational col­lapse. This is also supported by the lackof a significant amount of highly dissi­pated material in the form of a diskoThese and other more subtle points re­quire us to look for a non-dissipativetype model for IC 3370.

One alternative possibility may lie withmergers as these have been shown tobe capable of producing the charac­teristic box and peanut shapes (Binneyand Petrou, 1985). Their models showedthat the slow accretion of a satellitegalaxy by a more massive host can leadto the box or peanut shapes with theproviso that the mass of the bulge mustnot amount to more than a small fractionof the overall mass of the host system.However, for IC 3370, the ratio of thebulge mass to total mass is almost unity.Also, the satellite capture hypothesiscannot work weil in the case of the hostsystem being highly triaxial, a possibility

Upgrading of the ESO 1.52-rn Telescope0. ALLOIN*, Observatoire de Paris, France, and 0. HOFSTADT, ESO

A Few Words of History

At the time the ESO Convention wassigned, two telescopes 1 metre in sizewere foreseen, one dedicated to photo­metric observations, the other to spec­troscopic work. The latter however, wassoon turned into a 1.52-metre tele-

• Chairperson of the ESO Users Committee

scope, a modified twin-brother of a tele­scope then under construction at theHaute-Provence Observatory. A ratherlarge building was planned to house thecoude spectrograph and an aluminizingplant for up to 2 metre diameter mirrors,and was erected in 1968.

The 1.52-metre spectroscopic tele­scope was first offered to visiting as­tronomers for the period September 1sI

1969 to March 1st 1970. The instrumen­tation then available consisted of thecoude spectrograph and a Cassegrainspectrograph from Marseille Observa­tory, aimed at radial velocity measure­ments. Later, an echelle spectrographwas installed at the coude focus, work­ing with an electronographic deviceand providing a resolution down to0.015 nm. This spectrograph is present-

18